Zombie Invasion HD, previously known as Defense Craft, has just seen an update for the iPad. Why any of this required a name change, which subsequently led to a bunch of time wasted trying to figure out why the heck the game I was trying to link to didn't exist, is completely beyond me. However, it's a thing and it exists now. Best to talk about it.
Whatever it's official name is at this point, the game is primarily about tower defense. Players fend off hordes of weird floating zombies using even weirder towers. The original release offered up close to 25 levels, multiple enemy and tower types as well as a handful of themes. This update increases the amount of stages on hand, giving players even more zombie-fighting goodness.
As some added incentive, Zombie Invasion HD will be free for the next few days. Why not take a look? Try out some of those new levels perhaps?