This game is more than i can describe, got every thing, beautiful weapons, enemies, vehicles, you have to try it now ...
When i started it, it was a bit hard for me to play well, but when i began to restore health it became a little easier, just a little not much, but when i reached about half the game i found my self being over run by enemies from every where, and in the final stages of the game they became even more stronger and smarter only trying to kill me even if they died trying to :D
After the last stage i couldn't believe that i finished the game, it was so enjoyable, it was like a true war against an alien invasion except you are not 100 % human after all you regain health with time :D
The weapons are beautiful but some of them have a very few ammunition around ........................., other than that the bigger your gun the greater ..............................................
There are a variety of enemies weak and strong, and even the weak evolute to a stronger one as you progress to the final levels, and even the small enemies will give you a hard time if you don't keep an eye to where they are coming from, so watch your back
The Co-Operative mode is a split screen mode, i didn't try it, so i can't tell you anything about it ..............................
Over all i guess this game is great and you have to try it and add it to your collection ................................