Awkward first person shooter combat. The "feel" of the fights on ground doesn't feel right.
Maybe it is mostly due to the animations of the characters and that the impact when one hits them doesn't give as good of a feedback as it could have.
Some of the vehicles are quite fun to drive and the "jump pack" for the Strogg, but it doesn't make up for the bad "ground fights".
I must also say it's a pretty difficult game to get into, but I can imagine the concept with all the missions can be quite rewarding when one gets into it. But still. It's how the game "feels to play" that ruins it for me.
Graphics are quite good occasionally (well, maybe not for end of 2011).