I have 3 major complaints.
1. The level after the zombies is too frikkin' hard. At least have the zombies spawn fucking weapons so we don't go in unarmed and ready to get destroyed.
2. The bodies and shells never disappear, the camera shakes too much, and all the blood stains hamper your vision. The first two cause serious fucking lag, as everyone and there dog has mentioned here.
3. Picking up and dropping weapons is too much of a fucking hassle. I would rather have had the ammo system from the last 3 games, except that people with assault rifles would rop AR ammo, shotgunners would drop shotgun ammo, and so on.
Why on earth would you think to put the arrows on tow separate lines? Each time I see a key on the top line I press up regarless of wheter it's the up key or not.
This game sucks. There's no health-o-meter, shooting the viruseseses just makes it harder, and i can't tell what kind of effects the viruseseses (besides red) have.