We borrowed Kirby's Epic Yarn for Wii over half-term. It's a delightfully inventive game and I'd recommend it for children of all ages. It's quite forgiving, but that doesn't make it easy. One of the things that struck me was the variety of music on the soundtrack.
Before I cover that though, some thoughts on computer games music generally. Because gaming doesn't occupy a high place in popular culture compared with its turnover, and because it's mostly background, I think it doesn't generally get thought about. Recently, though, the Royal Philharmonic Orchestra played a concert to mark 25 years of Legend of Zelda.
Mostly it seems like it's pretty generic stuff, see Exhibit A - the music to Da Blob. However even the music on that is cleverer than it appears as the melody only plays while you're painting, but cuts in and out at the right moments.
The World of Goo music is quite distinctive and I think it sounds like a film soundtrack. You can even download it.
Back to Kirby - someone's collected all the tracks up. I particularly like the sparse piano track on lava landing.