Elevator Pitch

Designed to be as aggravating as it is addicting, Reaction Line is a minimalistic, hardcore, single-player game where you have a single objective: sort lines into red and blue stacks as quickly as possible. The catch? You only have one life.

Pick your poison: Timed Mode on the left, Infinite Mode on the right.


Reaction Line was developed while I was studying at the Make School Summer Academy in 2015. While players can select from one of three gamemodes to play from (Timed, Infinite, and Evil), the mechanic is the same throughout: sort the lines on the screen by tapping the color on the bottom that matches with the next line in the stack.

This sounds simple enough, but if a player makes a single mistake, the lines on the screen “break” and their run immediately ends. This makes for some slightly irritating yet extremely addicting gameplay—try handing the game to a friend to try out and watch their expressions as they figure out how to play the game.

Screenshots of the main menu flow.


I programmed the majority of the app in Swift using the open-source game engine cocos2d-objc. I also added Mixpanel for analytics.

Figuring out how to avoid memory errors was probably the hardest challenge I encountered in the creation of this app, as the large stack of lines generated on each run would inevitably cause the app to panic and crash about halfway through each run due to insufficient memory. To solve this, I only spawned enough lines to fill the screen’s height, and simply recolored line assets when they moved off screen and teleport them back to the top.


I went for a minimalistic design and based my color choices off of those that went well with the primary beige background. Also, I’m generally opposed to placing separate, darker objects or panels underneath text just for contrast, so I added drop shadow where necessary to make the HUD more readable.

In terms of movement design, the only major animation in this game is the lose transition. When a player makes a mistake, all of the lines on the screen suddenly become askew (accompanied by a satisfying boing sound) and begin to fall down the screen. I spent a lot of time on this one because I figured that this was the animation that players would see the most. (I’m evil, I know.)

It took several iterations to convey just the right amount of joy/disappointment at the end of a round.


At the Demo Day at the end of the program, Reaction Line (along with Tile, Tap, Push!, another project I worked on while at Make School) won the “Audience Choice” award as voted by the vistors in attendance. As a result, I was able to present both of my projects in front of everyone (approximately 100 people). I also received the “Student Choice Runner-Up” award as selected by my fellow students in the program.

You can view a video of my entire presentation here. Reaction Line is also available on the App Store here.

Reaction Line was released in July 2015.
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