I know what you're thinking. "Isn't that the lame tower defense game that's vaguely related to Warhammer?" No, this is the other new-ish Warhammer game—the good one. Warhammer 40k: Carnage is a side-scrolling shooter filled with chainswords, jump packs, and all the other gear an Ultramarine needs to get by. It's usually a $7 game, but now it's down 70% to just $1.99.
There are a ton of levels in Carnage, and the most recent update added a new map along with more characters and items. You can even replay levels with different variables like heavy gravity, more powerful enemies, and so on. As you hack and blast your way through the ork menace, you'll find new items that change the way your character is played. Don't like ranged attacks? Go full melee. It's also a nice looking game with lots of neat lighting effects and clear textures.
The one sticking point is the use of in-app purchases. There is a plentiful in-game currency that's used for buying gear from the shop and upgrading items. Gold is a rare resource that can be used to purchase very high-value items early and revive your character partway through a level. These are definitely non-essential functions, and the game doesn't harass you about buying anything. IAPs are just tucked away in the menus if you want them. For $2, this is a great buy.