Helsing's Fire is an interesting little title with a pretty original gameplay premise. The idea is that you place torches in an area full of objects and walls, and you have to target or hide certain creatures with that light. The backstory of the game is about the adventurer Van Helsing and his fight against the undead, but it's more of a strategy title; the idea is to line up the light and shadows in just the right way in order to conquer various monsters on the playing field.
While it doesn't start out very tough, more gameplay features slowly get added (eventually you have to match color attacks with certain colored monsters, and you only get a set number of attacks per stage, so you have to plan things out pretty carefully). And while the backstory is really just a frame for the gameplay, it's got a fun edge to it; it's a nice satirical spin on the old "fighting Dracula" theme, and there are a few fun celebratory fist bumps in between stages with Helsing and his assistant.
For 99 cents, Helsing's Fire offers up a good bit of original gameplay that spans 90 different levels. A survival mode and full Crystal integration add some extra fun as well, so the game is well worth the buck.