Me and my friend found a perfect system and we got to level 34, but he screwed up and accidentally killed himself with a grenade and there was no way i could fend them all off :(

Took us 4 hours!

damn highest we got was level 22, no one could beat it...kept trying and trying.

Ive only played with my girlfriend on split screen and the highest we got was level 13. :P

Are you guys playing 2 player splitscreen or online with 3 other people?

2 player split screen, he owns a X360 but doesn't want to pay for online lol

WTF?! I'll blame it on my girlfriend's suckiness with FPS games then....

lvl 30, could have kept going too if I didnt have to go to work in the morning. we had a perfect strategy, that and everyone had either the flamethrower or ray gun or both.

also, it was with 3 others online.

Got to level 32 took us 3 hours..

Highest I've gotten to is 18 with splitscreen. Solo I made it to level 4 with only the knife(no grenades either, and no lucky insta-kill power ups), but I bet I could make 5 if I was smart enough to unlock the other rooms to run around some more.