Rhythm Racer [iTunes link] is an interesting take on the growing music/rhythm genre, and while it shows some interesting promise, it's currently a little too thin to become a full-fledged obsession. The basic idea is that you're controlling a ship down a track with different colored orbs on it, and as you hit the orbs in sequence, they play music -- basically, it's Guitar Hero where you're driving an accelerometer-controlled spaceship rather than playing a guitar. And that central mechanic of the game is fun -- you move faster the more orbs you hit, there are occasionally ramps to jump off of, and at its best, the game has that "just one more try" feeling that keeps you addicted.
The problem? There's only one track to play. The game is free (and the track is good -- it's actually a song by former Nerf Herder Perry Gripp, who's been doing amazing things with his Song of the Week site), but one track? The idea is that, by paying a little more via in-app purchase, you can pick up more to play, but there's still only one other track to pay for right now in the game. It's too bad; while the game is definitely worth the free download, they don't even have in-app purchases for you to follow up with quite yet.
Hopefully, that's easily fixed (and hopefully we'll get at least a few more tracks to play through soon). As it is, the game is more sort of a demo -- a demo for what seems like a fun game, but a demo nonetheless.