After completing my previous game, Block Drop, I wanted to do something completely different so I started experimenting with the Box2D Physics engine. Once I became comfortable with Box2D (it took a while), I started fleshing out the core elements of the game by introducing the rolling balls and then coming up with interesting obstacles and gadgets for them to interact with. When the idea came to make the balls annihilate each other, Collider really started to take off.
Collider took about two months to create. The first step was creating the basic game engine along with all of the game elements (pipes, gears, etc.). This was a time-consuming effort, but it was motivating to see the game environment come to life.
The most challenging part of the development process by far was designing all of the levels. Some levels happened really quickly while others required hours of grinding it out. Sometimes I'd work on level ideas all day and look back and realize that I had made no progress at all. I'm very happy with the variety of levels that came out of the process and, in the end, that makes it worth all of the hair-pulling, fist pounding days I spent making them.
The final step was adding sound. After adding the basic sound effects, It still felt very "empty" sound-wise. I decided that adding music was the solution. I took the basic music system that I designed while making Block Drop and turned it up a few notches. I've written a separate section about the music of Collider.
I hope you enjoy playing Collider.