Super Crate Box has been released on iOS as a universal app for 99 cents. The game first came out on Mac and PC in 2010 and is available as a free download from the developer's website, but we'd say it's worth the buck if you like it. Like Canabalt and Robot Unicorn Attack, it's survived the transition from Flash game to Flashless phone pretty well. The game has you collecting crates with weapons inside to get rid of enemies, and comes off like a turbo-charged, score chasing take on Defender and Joust with fashionably retro graphics and music.
The touchscreen controls are about as good and responsive as we've seen on a game of this type before (just as well, as the game is hard as nails), though we did find it easier to wrap our thumbs round the iPhone buttons than the iPad equivalents. For those who really can't imagine playing an arcade game without buttons, though, it works with the iCade peripheral. A note on compatibility — we tested the game on an iPhone 4, iPad and iPad 2 without issues, but some reviews posted in the App Store have noted that the game suffers from crashes on the iPhone 3GS. While owners of that device may want to exercise caution before buying, we don't have much hesitation in recommending it to others.
Update: the game's developer let us know that the v1.0.1 update is now live in the App Store, which should fix the issues iPhone 3GS owners have been seeing.