Well its easy realy first u need to keep urself in the starting room and stay there until dogs come when they come open the thompson room and buy the thompson kill the dogs and stay in the thompson room at round 7 open the stair and go buy a random box and turn power on then u stay there till round 9 then open the door that goes into the teleporter then u will see some stair go there and kill zombies then leave a crawler and go buy the random box keep buying it until teddy comes then it should up the stairs buy it every 1 round then buy juggernog go to the teleporter then look right theres a little exit go there and u will find a orange liquid in a jar without a lid aim at it and press x u should hear a noise if u do u upgraded the juggernog then keep upgradeing it like 15 times and kill the crawler and go to the stairs it should be round 11 or 12 so on round 13 make a crawler then u should have enogh money to use pack a punch link the teleporter and use pack a punch then go back and kill the crawler and then keep on doing it and then u should get to a high round if u good enogh hope that helped! :)