Space Frontier 2: Game Design in Depth


Space Frontier 2 is a space exploration game published by Ketchapp and developed by Part Time Monkey with Design by LynxSwamp.

The game tasks the player with exploring the galaxy one solar system at a time.

The player launches a multistage rocket into space and then taps the screen in order to detach each stage of the rocket. Detaching a stage reveals another rocket booster which propels the rocket further into space.


Each planet reached is colonized by the astronauts on board the rocket. These astronauts passively generate money that can be spent on rocket upgrades, more astronauts, and further exploration into the galaxy.


Core Loop and Metagame

The core gameplay for Space Frontier 2 is launching the multistage rocket into space to land on planets. The player repeats this process to generate money. 

The metagame is exploring the galaxy and reaching new solar systems. Each new system contains the same core gameplay as the first. The difference being that the rewards for rocket launches and cost of upgrades are all higher.


 Launch and Landing

The launch begins by tapping the rocket. Each additional tap will detach a stage of the rocket. The later the tap, the more money that is rewarded, and the further the rocket will go. However, tap too late and the rocket will explode.


The tap timing mechanic is represented by a circular dial that depletes in a counter clockwise direction.

There are 5 different ratings for rocket detachment: Ok, Good, Great, Perfect, and Impossible. The latter 3 will reward the player with money. In the first solar system, Great pays $10, Perfect pays $20, and Impossible pays $80.

These rewards increase in successive solar systems. The first 8 are shown in the table below:

System Great Perfect Impossible
1 $10 $20 $80
2 $10 $20 $80
3 $25 $50 $200
4 $45 $90 $360
5 $80 $160 $640
6 $135 $270 $1,080
7 $215 $430 $1,720
8 $315 $630 $2,520

The base Great payout determines the other two. Perfect is always twice as much as Great and Impossible is always eight times as much as Great.

Disregarding the first two planets, the payouts increase exponentially. This graph illustrates that point. You can see how much separation the Impossible eight times value makes the further into the galaxy the player explores.

Landing on planets also rewards money. The further the planet in the solar system, the more money that is rewarded. Just like the stage detaching payouts, these also increase exponentially between solar systems. 

System Planet 1 Planet 2 Planet 3
1 $45 $90 $135
2 $45 $90 $135
3 $75 $150 $225
4 $120 $240 $360
5 $195 $390 $585
6 $300 $600 $900
7 $450 $900 $1,350
8 $645 $1,290 $1,940

There are about a dozen planets in each system, however we only need 3 to notice the payout pattern. In each of the solar systems, Planet 2 is twice the value of Planet 1 and Planet 3 is three times the value of Planet 1. Therefore we can just use this equation to solve for the cost of each planet:

Planet X Reward = Planet 1 Reward * X 

This is simply a linear equation. However, the payouts between Solar Systems (disregarding the first 2) is exponential.

An interesting fact about landing on planets. As long as the rocket doesn't blow up, it will almost always land on a planet. There is a brief period before reaching the first planet where the rocket will just float in space endlessly. However, once the rocket passes the first planet, it will always land on one. 

I think this attributes to the casual nature of the game. It's really hard to reach a losing state. The game keeps pushing the player forward, skill will just help progress faster.

Rocket Upgrades

Rocket upgrades will add an additional stage for more boosting power. This enables the rocket to go further and land on more valuable planets.

In the first system, the cost for the first upgrade is $60 and then every future upgrade is $60 more. So the 5th upgrade would be $300. Again, this is a linear increase. However, between solar systems is again an exponential increase.

System Cost per Rocket Stage
1 $60
2 $260
3 $890
4 $2,210
5 $4,530
6 $8,170
7 $13,500
8 $20,800

When I say exponential I mean that we can match a polynomial equation to these data points.

Using a site like I plot the data points and can get an approximation of a polynomial equation up to a selected polynomial degree. If the degree is 2, then the equation would look something like:

y = a + bx + cx^2

A degree of 3 would add dx^3 onto the end of that equation. The higher the polynomial degree, the more accurate the equation. While I could just select a degree of 10, it's best to simplify the equation as much as possible while still staying accurate.

With the above data set (and some rounding) we get an equation of:

 y = 53 x3 - 129 x2 + 245 x - 118

We can then use this equation to make a prediction about future solar systems. If we plug in 9 for x then we get $30,400, which turns out to be the correct cost for the first rocket upgrade in the 9th solar system.

I think these kinds of equations are interesting to figure out because we can start to dissect the math in the design of the game. This is especially true for a game with idle mechanics like this one where how much money the player has is directly proportional to their progress within the game.


We've covered the basic way of making money within the core gameplay loop. However, the biggest money making venture comes from colonizing the planets with astronauts. This is done by simply landing on a planet while the rocket contains the little explorers. 

Each ship starts with 1 astronaut on board. The player must pay for each additional astronaut. In the first system, the first astronaut to board the rocket costs $1, the second is $2, then $3. A linear progression just like the rocket upgrades.

If the rocket successfully lands on a planet, each astronaut will generate money over time. In the first system, each astronaut generates $11 per hour. This is the idle mechanic in the game and is where the real money comes in.

It's worth noting that it does not matter which planet the astronauts land on, they all generate the same amount of money.

It should be expected at this point that I'm going to look at the costs and idle generation of these little space cowboys between different solar systems. Let's look at a graph comparing the cost to the per hour rate.

System Cost per Astronaut $/hour for each Astronaut
1 $1 $11
2 $4 $22
3 $8 $33
4 $13 $44
5 $21 $55
6 $29 $65
7 $40 $76
8 $52 $87
9 $65 $98
10 $81 $109
11 $97 $119
12 $116 $130
13 $136 $141
14 $157 $152

The hourly generation of each astronaut increases linearly while the cost increases exponentially. This means that over time it will take longer for the astronaut to make up for it's initial cost. Meaning that the further the player gets into the game, the longer it will take to get enough money to explore more solar systems.

In the first solar system, the first astronaut costs $1 and generates $11 per hour. So that astronaut is net positive after 1/11 of an hour or 5.5 minutes. Each additional astronaut will be an additional 5.5 minutes of time to become net positive due to the linear nature of the cost.

For the 14th solar system, the first astronaut generates $152 per hour while costing $157. That astronaut will be net positive after about 1 hour of real life time. Each additional astronaut is another hour on top of that. If the player loads up a rocket with 72 astronauts, that last astronaut isn't profitable until 3 days later.

This is one way the game is extended the deeper the player is in the game. If the player is already hooked on the game, the developers don't need to reward them with a new solar system nearly as often as early players.



Other than the standard banner and interstitial ads, Space Frontier 2 has a wide variety of rewarded ads. This is where developers get creative in their monetization efforts. 

How can the developers reward the player for watching an ad while also not making them feel like it is required to progress in the game? Good rewarded ads strike this balance well.

  1. Rewarded video to unlock new rocket skin

When the player lands on a planet, sometimes there will be a piece of cargo floating in it's orbit. These contain new rocket skins. To unlock it, the player MUST watch a video ad.


While I'm not sure I 100% agree with locking skins behind a 30 second ad, I do like that this rewarded ad has no affect on gameplay. A lot of the time, I did find myself watching the ad because I wanted some variety in my rocket.

An interesting bit about this is that the player finds the piece of cargo and will actually lose the cargo if they continue on without watching the ad.

This is a psychological tactic known as loss aversion. The game threatens to take away something that the player acquired through playing the game. We, as humans, don't like this. It is much more likely that we will watch the ad to avoid LOSING the cargo than if the situation was reversed. For example, if they said we could watch an ad in order to GAIN a new skin. The former is also much more immersive within the game universe.

This is a recent trend I have seen in a couple other games. Most notably Hooked inc by Lion Studios. Where the player fishes out a treasure chest full of the premium gem currency. The catch is that they can only get the gems inside if they watch an ad.

2. Rewarded video to add 30 astronauts to the rocket 

This is useful if the player is very impatient with the current pace of the game. Even if the player doesn't have enough money to add astronauts to the rocket, they can still keep doing that by watching an ad.

It's worth noting that the best strategy is to buy astronauts first and THEN use this rewarded ad because those later astronauts cost more money.

3. Rewarded video to increase idle profits

This will increase the colonizer idle profits by 2x or 5x for a certain amount of time. The 2x boost can be done anytime in the galaxy view. The 5x boost is acquired similar to the cargo and is represented as a satellite orbiting a planet.

This is a pretty standard rewarded ad and will just speed up the gameplay a bit.

4. Rewarded video to save the astronauts if the rocket explodes

This is by far my favorite. I use it almost every time because it really plays on loss aversion. Not only did the rocket explode but all the astronauts shoot out in a glorious animation. The player loses the astronauts, the money spent on them, and the time for that launch. Watching the ad reduces that loss.

Honestly, I think this is a brilliant rewarded ad mechanic. The player is not getting towards the goal faster, they are just not losing as much as they could.

There is also a paid subscription service. It's something like $7 per week and gives some bonuses. This is really just going after the whales and impatient players as it's really not required to progress in the game. Most of the benefit is just progressing through the game faster.


Comparison to Space Frontier 1

This game made multiple changes from the first game.

  1. Bigger and better metagame

The first game was limited to just 3 planets. However, it takes more time to get to those planets than a planet in Space Frontier 2. It's about as equal to discovering a new solar system.

Where Space Frontier had 3 of these planet/solar system starting points, Space Frontier 2 has somewhere in the ballpark of 100.


There is also no metagame screen in the original. The galaxy view really encourages exploring new planets and gives the player a good sense of progress. I actually had to look up online if there were additional planets in the original because the game doesn't spell out a definitive end.

2. Different rocket detachment mechanic

The first game had an integrated rocket detachment mechanic. Each rocket stage shrunk up into the rest of the rocket and the player had to tap when it was almost to the next stage. This is in contrast to the simple circular dial in the sequel.


I would argue that there are positives and negatives to both. Most people I've talked to believe that the original mechanic was better because it was more immersive. And I agree, it was much more immersive. However, it was also hard to know when to tap. The rocket literally goes up into itself, which means the player can't clearly see when to tap for a perfect rating.

I think some kind of middle ground could have been achieved where the player has a better visual indicator of when to tap combined with a more immersive mechanic.

Game Juice 

Game Juice - additions to the game that increase responsiveness to player interaction and a sense of good "feeling". Most of these don't affect gameplay and are visual or audio in nature.

  1. Rocket Lerp

First, lerp is short hand for linear interpolation. This is a method of fitting a curve to construct new data points within a range of known points. 

One of the coolest things the developers use this for is when landing on a planet and discovering a new solar system.

There are 2 known points, the starting rocket point and the landing point. Instead of just using a straight line, the rocket goes in a non-linear path.

In the instance of landing on a planet, this looks like the ship gets stuck in the planets gravitational pull as the rocket flies past the planet. It slows down until reversing course to land on the planet.


The lerping for discovering a new solar system is less representative of real life physics and more just for fun. The rocket will do a large loop before arriving at it's destination.

2. Adding astronauts to the ship 

Every time the player taps to purchase an astronaut, a tiny suited up human will appear on the launch pad and board your ship. Doing this a bunch of times in a row is very entertaining as loads of space explorers board the ship all in a line.


3. Rocket detachment

This whole process is just really juicy. The circular dial has sparks coming off it, tapping turns the whole dial a color related to how well you did. At the same time the rocket stage detaches and flies off into space as the rest of the rocket keeps thrusting upwards.

 Final Thoughts 

I think this game excels at different aspects of what makes for a good casual game:

  • It has a simple core loop that is very juicy.

  • The metagame is well incorporated into the theme of the game and keeps the player moving forward with a good sense of progression.

  • There is a variety of rewarded ads that feel fair to use but not necessary to progress through the game.

  • The graphics and sound effects are high quality and cohesive.

Of course there are always improvements that can be made. 

Tap Mechanic

The tapping mechanic could be more immersive. They took a step backwards from the first game in that respect.

Metagame Gets Old

The metagame got pretty old after a while. I think this is hard to avoid with casual games. Everyone will get bored of the core gameplay at some point and for me it was after 25 solar systems.

More specifically, I reached a point in the game where I almost stopped worrying about money. At about solar system 15, I discovered that I was making so much money from that system, that I could go back to system 1 and very quickly max it out to 1000 astronauts. At the current moment, I am at system 25 with all previous 24 systems maxed out. Every day I generate enough money to explore a new system with enough left over to max out the previous system.

With this strategy, I can check into the game once per day and explore one more solar system. It was at this point that I got pretty bored with the game. The sense of exploration had come to an end and there were no new mechanics to discover. 

I have also been able to figure out how long it will take me to explore the next galaxy. By comparing my hourly income to the cost of the next solar system. I found that the time to do so increases steadily.

In the table below, for each current system I have 100 astronauts and a max of 1,000 astronauts in all previous systems.

Current System Next System Cost Hourly Income Time to Next System
20 $19.3mil $2.08mil 9.28 hours
21 $23.2mil $2.29mil 10.13 hours
22 $27.6mil $2.52mil 10.95 hours
23 $32.6mil $2.76mil 11.81 hours

The time to next system is calculated by taking the next system cost and dividing it by the hourly income.

This means that the later solar systems will start to take multiple days to explore. Of course, there are the rewarded ads that will double your idle income so progress could be sped up.
One thing that each new solar system brings is a new rocket 'invention' that changes the appearance of the rocket. It is cool to see the rocket evolve but not enough to keep me going, especially if those 'inventions' don't change the mechanics of the game.


I hope you enjoyed reading this design analysis of Space Frontier 2. Please comment here or wherever you found this article so we can continue the discussion! 2: A Natural Difficulty Curve

Intro 2 is the follow up to Voodoo's breakout hit is what originally landed Voodoo on the mobile gaming map. Now, after a dozen more games and becoming a top mobile publisher, Voodoo comes out with the sequel.


I'm going to take a look at 2 from a game design perspective. I will look at the overall flow of the game, the design of the difficulty curve, and a psychological trick that will keep players coming back.

Basic Description

The objective of the game is to control 100% of the arena. You play as a small, ever moving square with a small starting territory that corresponds to your square's color.

There are other players that start the same way and have the same goal.

In your own territory, you are safe. When you leave, you create a trail that draws onto the arena. If you make it back to your territory then you gain control of the territory you just traversed.


If someone else hits your trail, you die, your territory is lost, and you must start over.


A major difference between 2 and the original is how you move. In the original, you could only move in 4 directions: up, down, left, and right. Now you can move in any direction. The arena is now circular instead of square to complement that change.

Game Flow

The game starts with a screen displaying your current character and your high score, which is displayed as a percentage of the highest area you have conquered.

You may select any characters you have unlocked and then start the game.

You conquer territory and kill other players until you die. You are then presented with an opportunity to watch an ad to get an extra life or decline the offer to return to the main screen.


Game Mechanics

First of all, this game is not played with other humans. You are playing against bots. This means it's a free-for-all between you and a bunch of AI.

You are dropped into an ongoing game, which means some bots could already have taken a chunk of the arena. 

New bots are also added throughout the game. So no matter how many bots you kill, they will just keep coming. The only aspect of their spawning that you can rely on is that they will never spawn in your own territory.

The number of bots compared to how much territory you have conquered directly correlates to the difficulty of the game.

At the start of the game, you spawn with 0.66% of the playfield. If there are 10 other bots, then there is 99.34% space for them to occupy. If you own 50% of the arena and there are still 10 bots, then they are in the other 50%, a much more concentrated area. This makes it harder to venture out of your territory without bumping into someone else.

This is one of the ways the game gets more difficult. Less space but the same amount of bots. Towards the end of the game, any free space would get used to spawn another bot, creating a hectic situation.

This balance of space to bot count could be managed itself by AI, potentially decreasing the amount of bots as space becomes cramped. 

The other way the game could manage difficulty is the AI of the individual bots. The bots are tasked with taking space and killing you or the other bots.

In order to increase the difficulty, the bots just need to be more aggressive toward the player, attacking you whenever you leave the safety of your own territory.

If you kill an aggressive bot, the game just spawns another in it's place. The life of one individual bot doesn't matter much.

I could be over analyzing this and I don't actually have any data to back that claim up. But it's the only other major way the game could scale difficulty. 

Getting to 20% or even 40% has not been too difficult. However, I think it would take a long, long time to achieve 100% due to the difficulty curve. At a minimum, you would have to be very conservative when taking territory which would end up in a very long play session. 

My high score of 48% took about 10 minutes. And guess what, there is no pause button!


So knowing what we know about the AI, we can come up with some strategies to get the most area possible.

  1. Take the walls

The edge of the arena is the safest place since there are no enemies there. You put yourself up against a wall instead of being surrounded by the bots. You also can't die by hitting the walls (unlike 1). 

2. Wait until you know you can kill someone

The AI are bound to slip up. It's pretty easy to chill in your territory and watch a bot until they leave their space. Then, once they are a distance farther from their own territory than you are to their trail, you can strike with high certainty to kill them.

3. Take enemies space directly after killing them

When you kill a bot, their territory disappears. This is the best time to take a risk and capture the space. This is because you know other bots are not likely to be there. Just be careful of a new bot spawning in.

4. Don't venture out too far

This might be obvious, but my deaths always come from going out too far. Someone then comes into my field of view and I realize there is no way for me to make it back.

This limited field of view is what makes this game so difficult. If you could see the entire playfield at all times, then winning becomes much easier.


The only metagame is unlocking new skins.

This is achieved by completing certain stat based challenges within the core game like getting 75% of the arena space or killing 25 players in a single round.


The skin changes the character and also the territory that you own, changing it's color or pattern.


Metagame isn't as required in a pure competitive game like this one. There is nothing to upgrade or currency to gain. The motivation comes down to skillfully earning that 100% victory.

Psychological Tricks

Speaking of that 100% victory. It's displayed as a percentage on purpose. 

One of the things we've been trained to do in games is fill those percentage bars to 100% to 'complete' whatever task it was asking us to do.

The Zeigarnik effect, discovered in 1927, describes the phenomenon of finding it easier to recall a task that you have started, but not yet completed. 

Completing a task gives a sense of closure, a release of tension, and apparently, a departure from our memory.

Now most games have progress bars that tap into this effect and our drive to be completionists. Quest logs in RPGs or leveling systems in multiplayer games are just a couple examples.

So why do I point it out for this game in particular? Because there's only one quest. Just get that one bar to 100%. Should be simple, right? The thing is, I think you'll be playing for a long time to complete this one quest.


There are 3 ads and 1 IAP in the game:

  1. A banner ad at the bottom of the screen at all times.

  2. An interstitial ad after you die.

  3. A rewarded ad that revives you 1 time during the game.

  4. One IAP to remove ads.

This is a very common formula for Voodoo games. It's sticking ads in all the places that don't intrude on gameplay. The revive mechanic is very common in casual games. Players will use it when they capture enough territory that they think it merits a use to not lose their progress (me included).

I'm still surprised Voodoo doesn't include skins that can only be purchased using IAPs. It's something Ketchapp and many other casual developers do. It doesn't change the gameplay but is available to those who really want them. The omission of these must mean that Voodoo doesn't think they are worth the development cost of putting in.

Another IAP that Voodoo could include is paying for extra lives. I'm actually very happy this is not included since that's just pay to win. Voodoo would then be incentivized to make the game even harder, forcing you to pay money in order to get 100% completion.

With what they currently have in the game, I feel the ads are fair.

Game Juice

Here I like to highlight aspects of the game that don’t affect gameplay, but really help make the game 'feel' good. 

  1. The game shows the percentage you acquired after every successful territory grab.


2. Particles shoot up when you are in someone else's territory. (see above)

3. The game has a crown on whoever has the highest percentage. AKA the king.


This may not have a gameplay affect but it can have a psychological one.

If you see the king, you are more likely to want to kill that player. If you are the king, then it feels awesome to know you are the top dog.

3. The death animation is a 3 step process that draws out your agony.

First your line disappears. Then you explode in a satisfying animation. Then your territory fades away.


This is all much better than everything disappearing at once. It's more satisfying to kill other players and more dreadful when you die.

4. You are shown your territory after you die.

This is a really cool improvement from the previous title. Since you have a limited view of the game space, it's nice to get a whole screen view of the territory you conquered.


Similar Games

There are many, many io type games where you are playing against a bunch of bots or humans to become the biggest or strongest.

In terms of this specific io game, the most similar is It's another space taking game and has the same free form movement of this sequel. There are hex shaped spaces that you take. I assume this was probably a little easier to program than the free form shape in 2.


Another similar game is, which is basically the same as, but with different metagame mechanics.


Of course, I should probably show you what the original looked like as well.



Not something I would normally write about but there is definitely a game breaking bug in here. There has been multiple instances where I have owned 40%+ of the arena and then suddenly I have <1%. Like someone took some of my territory and instead of taking away that small chunk, the game took away the larger area. Somehow the logic to determine which territory to take away is off.

Either way, I suddenly lost all my territory in a very not obvious manner. This deters me from continuing to play the game. Why should I keep trying to get 100% when I keep dying like this?

I caught it happening in this video. I was at 11% and then my space disappears. I did a video instead of a gif because you can hear my live reaction haha.

Conclusion 2 takes the classic io competitive gameplay and makes enough tweaks to the original to have a quality sequel. 

For me, by far the most interesting aspect is the AI and difficulty curve.

As you conquer space, you naturally make the game more difficult for yourself. It's really quite elegant.

It's still unclear how much tweaking of bot AI and bot spawning there is. Who knows, if I was able to get to higher percentages, then maybe I would see a noticeable change.

Let me know what you thought of this write up! Would love to discuss your thoughts on the game and the design.


Happy Glass — Game Design Analysis

Basic Description

Happy Glass is a free physics based puzzle game by Lion Studios. A developer that has been able to put multiple games on the top charts recently.

Happy Glass has reached the top charts in both stores, peaking at #1 on the Play store’s top free games.

The objective is to guide the water into the glass by drawing lines on the screen. Every one of the 500 levels has a set of obstacles to guide the water through and eventually fill the glass. The player is then given 1–3 stars based on how much they drew (less is better).

New obstacles and game mechanics are introduced to increase level variation and difficulty.

Similar Games

Like many mobile games (fine, all games), Happy Glass takes it’s mechanics from other popular titles.

The drawing mechanic has been done many times before. In fact, Lion Studios has another physics based drawing puzzle game called Love Balls.


A game I played a lot that also falls in the drawing puzzle category is Brain It On! Each level has it’s own objective, but you are still drawing to achieve that goal.


The water mechanic has also been used in many games. Most notably in Disney’s Where’s my water? Where you guide water to help Swampy the alligator take a shower. This game has a removal mechanic instead of additive. Instead of drawing lines, you are removing dirt to help guide the water.


Game Loop

The core game loop in Happy glass is the same as other level based puzzle games.

  1. The player is presented with a puzzle.

  2. The player completes the puzzle.

  3. The player is rewarded. Go to 1.

The gameplay is not infinite, it is based on a series of handmade levels.

One small tidbit I’d like to point out is that clicking start skips the level select screen and jumps straight into the level you are on. This is something I like, because they are just getting me to the game faster.

Flow Diagram.png

A metric I like to take a look at is the time between rounds. How fast can you go from winning one round to starting the next? Happy Glass has a quick turnaround at about 5 seconds.


Gameplay Mechanics

There are many, many different mechanics that you must puzzle your way through in Happy Glass. I’m through about the first 200 levels and here is a glimpse of what I’ve seen so far:

Immovable objects

Screen Shot 2018-10-10 at 5.34.11 PM.png

Movable objects

Spinny thing

Screen Shot 2018-10-10 at 5.33.22 PM.png

Hot surfaces (remove water)

Screen Shot 2018-10-10 at 5.33.46 PM.png

Non-drawable area

Screen Shot 2018-10-10 at 5.33.54 PM.png

Multiple glasses

Screen Shot 2018-10-10 at 5.34.22 PM.png

Multiple spouts in multiple directions

 Imagine this…but another one!

Imagine this…but another one!

Glass direction

Screen Shot 2018-10-10 at 5.41.38 PM.png


A game with 500 levels has enough content to keep players hooked for a while, however, Happy Glass still has some light meta content.

The main meta mechanic is unlocking new skins. Some people might disagree that a simple skin store doesn’t qualify as a metagame, but it’s the closest thing in Happy Glass. You are still playing the core game over and over in order to complete the meta game.

There are different colors for the water, faces for the glass, and pencils for drawing.

There are 15 colors for the water at 1000 coins each.

There are 11 different faces ranging from 150 to 4000 coins.

There are 10 pencils ranging from 150 to 2000 coins.


That is a total of 36 different unlockables costing a total of 43650 coins.

Ideally, I would calculate how long it would take to unlock all of these skins, however, the coins can ONLY be obtained by watching ads or buying coins with real money. There are no coins achieved for completing levels.

To be fair, there are new challenge modes that you can acquire coins from, but the amount of coins is very low, the gameplay lacks longevity, and I’m really just focusing on the main game.


The IAPs in this game include removing ads for $2.99, and purchasing various amounts of coins.

There is a banner ad at the bottom of the screen at all times. Interstitial ads run between levels every 2–3 or so.

There are several rewarded video ads.

  1. On the IAP page, you can watch an ad for 100 coins. This seems to be an infinite use item.

  2. When you finish a level there are multiple things that could happen. If you don’t get 3 stars, you have the option to watch an ad to get that third star.

Screen Shot 2018-10-11 at 4.05.43 PM.png

If you do finish with 3 stars, then you can watch an ad for a random reward. There are multiple chance based reward games in Happy Glass.

3. There is a spin the wheel type game.

Screen Shot 2018-10-10 at 5.40.35 PM.png

4. There is a random prize machine game.

Screen Shot 2018-10-10 at 5.40.40 PM.png

Both will give you a random amount of coins between 25 and 250. You can also earn light bulbs which are used for in game hints.

5. Occasionally when you finish a level, you can watch an ad to get one of the expensive skins for free. Wow! That’s a 2000 coin value! Just for ONE ad?? /s

Screen Shot 2018-10-10 at 5.40.44 PM.png

Of course, the random games are probably weighted so that you are more likely to get the lower prizes than the big jackpots.

There could also be some unknown conditions that trigger the free skin prize. A theory of mine is that they give this option to you if you have resisted the other rewarded ads. But it could also just be a 1/10 kind of thing.

I would love to find out, but I’m not going to watch a bunch of ads to figure out the prize probability.

Game Length

The game’s length comes down to how long it takes you to finish all 500 levels and if you want to get all 3 stars or not.

I ran 2 tests timing how long it took me to play 10 levels. Test #1 took 5 minutes, or 30 seconds per level. I did not get stuck on any levels.

Test #2 took 10 minutes, or 1 minute per level. This time around I did get stuck on a couple levels.

I’m going to take the average here and extrapolate to come up with a very rough estimate for how long it would take to complete the game.

7.5 min (for 10 games) * 50 (to equal 500 levels) = 375 minutes or 6.25 hours.

Considering I only play any given mobile game for 5–10 minutes at a time, this game will last me a while (assuming I don’t get bored first).

I don’t factor the skins in the length because I don’t have the average coin output per ad watched.

Game Juice

I like to take a look at the game’s ‘juice’, also referred to as game feel or game responsiveness.

These are things like animations and sound effects that occur when the player interacts with the game in a certain way that makes the game ‘feel’ good.

Happy Glass covers the basics like button movement when you tap and coins physically moving to your counter.

Juice that is unique to Happy Glass is that the pencil waves back and forth when you are drawing.


Another cool piece of juice is that the face changes depending on how much water is inside of it. No water produces a frowny face, some water produces an ‘O’ face, and a filled glass produces… wait for it…. a HAPPY face.



Happy Glass merges the drawing and water mechanics in a simple yet fun puzzle game. The shear amount of levels keep this game playable for hours.

I would have liked to see an in game way to get coins. Achieving the skins ONLY through ads or IAPs rubs me the wrong way. However, since they are only skins, it’s something I can live with.

You can download Happy Glass for free on iOS and Android today.