Round 1: knife all the zombies repair the barriers if needed
Round 2: shoot a clip into the zombies then knife them, if at a window just knife them
Round 3: buy an M14, 2 shots to the chest and a knife or aim for headshots
Round 4: open the top door and go onto the lander buy an MP5K for a back up weapon
Round 5&6: stay on the lander area aim for headshots
Round 7: make a crawler go open the gate next to the
MP5K and open the door upstairs use the box until you get a good weapon and activate the power
Round 8: open the door to Juggernog and buy it use the box after if you have any money left call the lander to the station it as an escape route
Round 9: Go defend Juggernog from the monkeys
Round 10+: Suvive at the lander and at about Round 13 open all the doors and use all the lander launch the rocket and pack a punch
Hope this helps! :D