I got to level 46. you can get the Usi on round 3 if you're quick enough. then head straight to the random weapon locker. I usually go for the Tenelli M5, the Defender, and the sniper rifle (I forget the exact name, but its the one that costs $2,000). Then Just after I finish a wave I hang out on the other side of the map by the med dispenser. every single round I make sure I get anaphrodesiacs and just stock up, I make sure to have SIID-2 on me at all times. the wonder weapon is useless so I dont even bother opening the door for the keycard