Nice game, it's remind me a bit of Bionicles, the first one, 3D graphics in a 2d environment with a simple but solid mechanics, are the coins 3D or did you render the sprites?
Actually, everything except the gameplay is 3D. The cave is just really flat on purpose so that its not too confusing where the walls are actually dangerous and where they are just deco in the background. It becomes more obvious when you get out of the cave ^^
