We've already told you just how awesome Fish Labs' Galaxy On Fire 2 is in our review, which hit almost exactly one year ago. Since then, the original title has been updated a few times, and a DLC pack hit. In addition, Fish Labs had been teasing a high definition version of the game initially running on Tegra devices for way too long.
Well, that HD version hit earlier this month as Galaxy On Fire HD, released exclusively for A5-equipped iOS devices. It's even universal, to run on either your iPad 2 or iPhone 4S. Better yet, it can use either OpenFeint or iCloud to sync progress between devices. It launched with a few technical hiccups which kept us from sounding the alarm to go out and download it immediately, but those things have all since been fixed in subsequent updates.
Galaxy On Fire 2 HD is the exact same game as Galaxy On Fire 2, with substantially better graphics. If you already own Galaxy On Fire 2, there's basically no reason to "upgrade" to the HD version unless you just want some additional eye candy. However, since the game is so "old" (in App Store terms, anyway), it wouldn't surprise me if there's a bunch of people out there with 4S's or iPad 2's that never heard of it the first time around-- In which case, there's no better time to hop on this awesome game.