The first thing I noticed when opening this was some SERIOUS lag - seems like it's in the game logic loop rather than the render loop. Without looking at the source, I'd guess maybe related to the coins jumping around constantly (poorly optimized randomization)?
The coins jumping around also seems a bit odd - I couldn't really discern enough of a pattern to really boost my score, other than staying away from the creeper. I'd suggest either having coins that move along random paths, or just having a timer as the score.
Some of the graphics were a bit odd, too - I'm fine with the simple graphics, but if you're gonna use a creeper, you should really add at least ONE frame of an explosion ;). Also, it appears that the trees aren't actually obstacles? That surprised me quite a lot - misleading visual cues.