PickGrid was an experimental game built in Unity using no textures or lights. The idea was to make a completely procedural game using no assets and make it super optimized for performance, but for the sake of quick prototyping I used 3D meshes as the only kind of asset. The game uses no textures and no lights - all the materials are unlit. The game never uses more than 6 draw calls at any time.
The gameplay is pretty simple: analyze and pick a grid where the bots won't go when they start moving. Bot behavior is simple as well, it turns left or right when it encounters a block - the complexity is defined by level design. The game also has a level editor for users to create and share their own levels.
I never released this game to public - this was an experiment that served the purpose, but there were not enough levels and the difficulty progression scale wasn't linear with the 12 levels I had made.