I've played quite a bit on the online demo, and its very entertaining. There's more depth to the classes than in COD4, and depending on your load out you will play differently. The ranking system is similar to COD and you unlock weapons and also the extra's by ranking up and doing other things.

The most original part of the game is probably the destructible environments. If there's a building in the way, blow it up with a grenade launcher, if there is an inconvenient wall placed in your path, blow it up. This system takes away the safety of buildings and other destructible cover, and makes the player be more mobile.

There are some bugs in the game, sometimes I've had problems with framerate and also some freezing, but I would think this would be fixed by the full release which I am seriously considering picking up.