I bought this game for $3.96. I gladly would've payed $20.00. Mindless fun at its best.
The only real complaint I have is with some of the controls and camera angles. It's very hard to jump on platforms (thankfully it's only near the end of the game that you'll have to do it) cause Grave doesn't really jump. He dives. But there isn't a whole lot of jumping in this game. Sometimes you get stuck and the camera won't move. And the sheer amount of enemies that can appear on screen is overwhelming at times, but at least this game makes you want to keep going no matter how many times you die. It's a great game, and I definitely recommend picking it up since it should be around $9 now.