First you want to buy Quick Revive.

Round1: Shoot 5 bullets in every zombie and finish them of with a knife to earn around 1000 points in the first round.

Round 2 and 3: Use the rest of your ammo and keep knifing. After round three buy two downstairs doors to get the AK74u.

Go back to the lobby and camp at the window on the top floor. You can easily line the zombies up that are coming up the stairs (just keep an eye in the top window.)

Buy ammo in between rounds if you need but run back to the top window.

Once you have enough points, make a crawler at the end of the round you're on and buy all the other doors to get to the theater room.

Turn on the power and link the two teleporters. If your crawler is still alive then fix all barriers and hopefully you will still have enough to buy Jauggernog.

Kill your crawler and if the zombies get ahead of you use the teleporter. Try to make a crawler in every round so you can leave it cool down and link every round.

Hellhounds come, camp back by jauggernog and have a good weapon.

As you earn money, buy pack a punch, and speed cola and double tap. Double tap is a very important perk to buy if you have a light machine gun.

If you feel you need to use the teleporter in between rounds, run around the lap linking the teleporters as you go.

This strategy helps me to get to round 35 easily but always try to save roughly around 5,000 points in case you are downed and need fresh perks.