Algeblaster was my first project after getting serious about programming again. It was going to be a space shooty game where you're secretly doing algebra without knowing it, but it was a little bit too complicated and ended up being confusing and frustrating to play. This is the last prototype before I stopped to work on other projects. It has the normal prototype along with a simplified version of the game that uses colors instead of numbers. For example, the "prime factors" of green are blue and yellow.
I spent 6-12 hours a day on this project for about three months, since it was how I learned C# and Unity. It's definitely rough but I learned a crazy amount during that time so I still think it's pretty awesome.