I had another obstacle idea overnight and have programmed it in: a sort of "pitfall" tile that you can only step on once before it becomes a hole. This allows me to do things like those "you can only step on each tile once" puzzles. Everyone loves those kinds of puzzles, right?

I'm up to twelve levels in total and I think I'm approaching the point where I can start wrapping up development and move on to things like menus. I'm almost there!