@jakecrump My favorite part of the game is when the UFO appears because you can a massive power up that can help you clear the level which is a little bit of a nice break from the nonstop action. It's great to see a game have a "physical" aspect to it. The tapping can really build up a sweat if you can believe that. When the zombies close in and the screaming aliens come at you fast you really need to have lightning fast reflexes to survive.