[X]

[Coolpick]

You're about to learn how to not suck at zombies. You will need at least 40 minutes to get to level 20, anything past that is up to you, I've spent literally all day playing like this, you can keep going forever. I chose to stop and kill myself at 42 because it got boring.

Level 1. Use only your knife! 130 points per kill.
Level 2. Shoot zombie in torso or legs 8 times, then knife the ######.
Level 3. Pump 8 rounds into the zombie's torso or legs, knife two times.
Level 4. 2 Clips into zombie and knife until dead.
Level 5. Go up the right set of stairs(run like ######) and open the next two doors, buy MP40 and whoop some ######.
Level 6-8. Remain in this room until it gets too hectic, open door, buy the MP5K for your pistol, save 1250 points for the next door.
Level 9. Do not turn on the power, head as far to the other side by the power switch as you can, there will be a window with some claymores, buy some and set them up at the window next to you.
Level 10-12. Keep doing this until over-run. Open door when too hectic.
Level 13. Keep opening doors, never sprint.
Level 14. Keep walking in the loop you've just created, make sure to leave one zombie for the next wave.
Level 15. Turn on the power, link teleporter.
Level 16. Get to the teleporter and use it when the zombies first reach you, when you get to the pack a punch, buy grenades and whip them at the zombies at the bottom level. Save one zombie, link teleporter.
Level 17-????. Do the same as the level before, keep your MP40, use the box (if you have a crawler) and keep trying to get a raygun/thundergun/monkeys.

I hope you find this guide helpful. I've got to level 42 using this strategy and use it to this day. Happy winning.
-Nick

PS: Pic related, it's probably you.

[abu_jwka]

Fairly simple and well known method anyway.

Also, your pistol runs out by level 2....


Good method though, I use it all the time