Tower Defense is nothing new, but Defense Grid adds all the right spices to make this the best arcade game yet.
If you havn't played tower defense before we suggest catching that guy that had you locked up in a dark room for the last 10 years and beat the snot out of him, then buy this game. The basics are still there. The enemy sends wave after wave and you have to build towers to slow them down and kill them before they leave.
The additions in this game make it so much better. Remember how slow some of the tower defense games were at parts? When you are ahead of the enemy and are destroying everything he sends at you it can get frustrating to wait for that final challenging wave. In Defense Grid you can double the time with a click of a button. When you have the resources to keep building, just go back to normal time. This turns a slow strategy game into a fast paced action/strategy.
Also, there is actually a story to it now! You'll fight along side the Core's AI that will help you along by explaining rules to the game and warning you when there are problems. You'll grow attached to him and he adds personality to the game. He also gives you a sense of protecting instead of just winning.
The towers are vast and all serve their own purpose. They can also be upgraded which adds some more strategy then just the usual "where should I put them?"
The game isn't a perfect ten however because of some bad descriptions of the towers and what they do. Also, there is a checkpoint system that is meant to help you go back and fix the mistakes that lead to your defeat but it's pretty useless and never sends you back far enough to make a difference.
The game has two campains and allows you to go back and play all levels with many different twists to add playability. Limited funds, limited towers, and limited cores (the little things the aliens are trying to steal from you) are a few that will keep you coming back even after finishing each level.
I have never got this much out of an Xbox LIVE arcade game and urge you, if you have the $10 in points and have ever played tower defense and liked it, BUY THIS GAME!