I recently bought the retail version of this game and I thought the game was very fun. Its very fast paced, so fast paced in fact that it cannot be compared to any other fast paced FPS like unreal, or quake. the game is innovative on its own. If you know about this game you know that you play in a mech robot and on foot. The seperation of these two types of gameplay keeps the game very varied having this type of gameplay keeps the game from being repetitive.
TIP
save very often, you can die in one shot especially when playing out of the mech