This game is a great arcade type-ish game, where high scores are your ultimate goal. There are many stages to unlock, so there's plenty of alien-whooping to be done. Some might find the design later on in the game a bit tedious, because essentially you're fighting the same enemies, albeit at a more difficult level. It will take a while to get the highest achievements in all the stages, since serious dodging abilities are required. This means there's plenty of gameplay hours in store for the gamer.
All in all I enjoyed this game (and still enjoying it). It is a great game that can be picked up and played whenever.