It is not bad like people said! It is funny to play! Believe me!
First the control system are great! Some people said it bad because they can not control this game clearly, it make them feel vertigo! But if you can control this game, you will feel very great! You can control it better if you have a Xbox 360 gamepad! Of course you can play it with mouse and keyboard on PC but it will a little bit more difficult!
The graphics use engine Unreal 3, it is not perfect like Gear of war but it is nice too look!
Sound is good too, gun shoot feel reality!
AI is normal, not good but not too bad! A lot of stupid AI from a lot of games out there! This game is fine with its AI!
If you played the demo and you feel it is too boring? It is just a short demo, too short so you can not see a lot of funny things in the full game! Don't just play demo and tell the whole game is suck! It is not fair!
The game run very smooth without lag or bugs, it run fine on my PC!
At last, the game is not perfect, of course nothing is perfect! But it is not bad, some people compared it with Mass Effect 2 or Bioshock 2! It is very stupid!
Try this game and you will see!