Rage is available in SD and HD versions and as the name implies the latter is aimed at the iPhone 4 and the iPad. The SD version is best suited to the 3G and iPod Touch, while the 3GS can run both versions, albeit the HD is somewhat pointless on the 3GS.
Gameplay is impressive and we expect no less from id, but graphics are what truly sets Rage apart from other iPhone games. Rage HD is truly in a class of its own and it just looks brilliant, much better than anything seen on any mobile phone. You just have to see it to believe it and you can check out a few gameplay clips here.
The only downside is the size. Rage HD will take up 743MB of memory, which might be too much for some users. Even the SD version goes over 400MB. However, Rage also has one major selling point, the price. The HD version costs just $1.99, while the SD sells for next to nothing, or $0.99 in the Apple world.