I love the use of mallets - there's something cryptic, yet comical about them, and the progression and repetition just fits them so well. The panning is a nice touch, and I absolutely concur that this is great background music, especially for a video game. I also think it starts to lose it's luster a bit after a while, especially when there are so many layers that the listener starts to lose a sense of climax. I might've started to crossfade some of the parts in and out intricately, just to add some dimension to the additive quality later in the piece. You also could've led up to the ending a bit more effectively. Still, if this is the "least creative" piece you've made in a while, that's pretty good. ;)