Tower defense may be the most overpopulated genre on iOS today, but there's good reason for that. They're simple to develop, and although the App Store has plenty of 'em, they're still really fun. To separate themselves from the herd, Backflip Studios is tying theirs into cult-classic film Army of Darkness.

That doesn't mean you have to have seen the movie before you play. The jokes and one-liners that populate the entire game will have more meaning for fans, but other people will certainly be able to get the gist of it.

The concept is simple: Defend your castle from the horde of undead that are coming for a specific book you have inside the castle: the Necronomicon. That's all you need to know. From there it's all gameplay. In a tip of the hat to Plants vs Zombies, AODD has you select five types of soldiers to use, out of 11 total. You'll also have to choose your special attacks, which knock back or harm large groups of enemies.

The only real fault of the game is that it starts off slow. Enemies come in at a snail's pace, and you recruit allies equally slowly. By the time the action starts to heat up in the early levels, it's over. Thankfully, the pace picks up later and the battles become longer and more intense. Strategy becomes more integral, and choosing which soldiers to bring out next and when to use special abilities elevates the game above mediocrity.

The bottom line. It's not complicated or innovative, but if you enjoy tower defense, you'll like it.