Neo Defender 2 is another title from the good folks at Appular, who we've talked about here on TUAW before. Neo Defender 2 is an Asteroids-style shooter, but the twist is that instead of moving around the screen, your ship stays firmly in the middle, leaving you to watch all sides and protect yourself from attacking shapes and forms. This lets you use mechanics like multi-touch on the screen to send shots out in all directions, and since enemies split and spread when you attack them, you have to constantly be on the lookout for where to shoot and keep them at bay.
Unfortunately, the game's progression is a little slow. You can eventually earn cash to upgrade your ship with extra weapons and more power, and while the fully upgraded player is a force to be reckoned with, I found that getting there could probably have been paced a little faster. I'd also have liked to see a little more innovation; maybe an option to tilt to aim the gun would have been interesting. Still, the game is quite fun, and bosses later on in the game mix things up between waves and provide some interesting strategy to play around with. Game Center integration would have been good, but OpenFeint does provide some achievements to chase.
Neo Defender 2 is only 99 cents for the iPhone, and it's available in an HD version for $1.99. There are lots of great iOS games out right now, and there are even more coming out this week, so it's possible you've already spent your iOS gaming budget this year. But if you want something a little smaller than the big profile holiday releases, Neo Defender 2 is worth a try.