(adsbygoogle = window.adsbygoogle || []).push({}); Okay, first thing about this is knifing confidence. Stabbing zombies is the only way to kill them for the first three rounds, don't shoot.
So, u spawn and there is an option here which doesn't really matter where you can buy quick revive now or after round one like I do. Then check the black window, kill the zombies asap if there are any and move to the upstairs window same again then the bottom window and finally the one under the stairs. Repeat this for the first three rounds, and if u go down remember to buy quick revive, later rounds are actually easier. My tactic is either 5000 points or over crowding which makes me leave and always go upstairs. Don't buy another gun. If u stick to knifing u should have enough to go straight through the portrait room into the foyer. Then buy an mp40.

If the random box is in either of these rooms dont bother with it an mp40 will keep u going till the power.

Okay so you're in the foyer with a possibly used pistol and an unused mp40. Look at the orange window and kill the zombies, but don't wait for them same for the mp40 window and the upstairs window, now make sure you're reloaded and go to the stairs blast em all to chunder keep going right through to the foyer then turn around and kill what's left.

If u have 5000 points now well done, u can move now. Others repeat the last rounds tactics. If the 5000 pointers *want they could leave but I would stand by the door and wait to be overcrowded then open up. Stand by the trap switch which can't be used yet and blast the zombies that come to you, kill as many as possible and if u get desperate go back to the next door.

This is your next, though short term camping spot mp40 again and take out as many zombies as you can before the need to reload and the closeness of the zombies makes you open the door. Shoot back at the zombies and hopefully it's late enough for you to not get hit in the back but keep checking.

At the end if thus round stand by the claymores and shoot the zombies by the orange window keep checking by standing by the power when they are about halfway to u turn on the power and go through, literally, the curtain. Sprint to juggernog and buy it you should have enough. If you have ammo left shoot the zombies, if not then run to the M14 and buy it because it's cheap and should still work. Stand at the bit where the gap us smallest right at the end of the but between the stairs and aim for the head as you always should. Go round and go back to all your camping points which weren't by doors (the little corridor where to zapper is after the lobby is another btw and the others are; the (now available) trap in the dressing room, and the stage where you blast back.)

The round ends, if you know where the box us quickly get one, if not get mp40 ammo.

The next tactic is a general one for all other rounds.
Do one circuit and come back to the stage turn left to the front of the stage and wait for the zombies run past the first few back on the stage and sprint and jump (not dive) from the turrets raised platform back of the stage to the stairs. Sprint round the bottom and past the teleporter (if you want to use it go now) and go past the boxes wait for the first zombies and run round the back with the horde chasing, if you have the thundergun blast them now while they're together and repeat the last instructions. If not shoot the crap out of them occasionally crouch to kill the golems (gas zombies but they look like him or it or whatever) if u have a ray gun go for the legs and create a crawler farm so u have back up on the end of round then the crawler dies thing.

Another general thing, when in the pap room don't shoot at the zombies through all grenades buy some more and keep going. This tactic pays for itself.

Final thing, some myths;
A) the ladder does not drop down it is immaterial shots go through it.
B) the ray gun is not always one shot kill upgraded or not but as far as I've seen a shot to the legs will normally crawlerfy it.

I got to round 41 with these tactics hope you enjoy them.