Summary: I love comet crash, one of my favorite games. It is missing online multiplayer but I rate it a 10 because it is amazing and ita graphics are great. I Would not call it a tower defence because tower defense reminds me of one of those crappy flash games on a computer.
Summary: The good: 4 player couch co-op!!! Good tower defense, a lot of depth in some levels. The bad: too many stupid levels where you have to do one thing very fast, some levels can be annoying. Game can get repetitive.