Four races..each with its own advantages and disadvantages. There are magic and tech items to buy (and surprisingly, everything works out as this is hard to implement without the game becoming a noobfest). Teamwork is a must...certain people must by certain things. It is great and addicting. THe maps are nicely designed.
It is a online only game...so it requires live to have fun with it. I believe you can still play with bots offline.