I like all the medals. This actually seems like something I would want to use in my math class (I'm a teacher). The hardest part to overcome is figuring out the different number system. These are basically just a digital version of standard math problems. I think the puzzles could do a better job of explaining their logic (showing the descriptions of the medals would be one way to do this) since these puzzles are already mentally taxing without needing arbitrary difficulty added in.