Round 21: open hotel, apartments.

-> When you need ammo, P1, P2 and P3 buy it at the start of the round. P4 stays in office.

Round 22-25: P1 defend apartments, P2 hotel, P3 alley, P4 office.

Round 26: ONLY P1 and P4: open power, get power, open roof top, get armor/perks. P1 defends apartments, P4 power station.
Round 26: ONLY P2 and P3: get quick fire and defend hotel/alley. P2 defends alley, P3 hotel.

Round 27: P1 alley, P2 power station, P3 apartments, P4 hotel

Round 30 Everyone keep in position. When you're done with your zombies, help the player with the boss.