We FINALLY figured out how to add trigger_levelchange without bugs into our maps!
Outside area (l0.bsp)
We have added an outside area to l0 (main map) with a gate. It is full of zombies and will give you a challenge.
Don't run out of AMMO!
Containment area (l0.bsp)
We have added a containment area to l0. How did half the zombies break out?