Open the gamemode
Survival Mode is selected from the lobby menu before joining a server. It disables the campaign and ramps enemy waves.
Wave ramp pacing
Waves accelerate around minute 10. Hold the corner of the largest room in the map and bait pursuit into a single entry.
Ammo economy
Survival Mode has fixed ammunition spawns. Memorise the map to know where every pickup refreshes.
Survival God badge
The Survival God badge requires a full 20-minute uninterrupted survival. Bring ranged weapons, conserve healing, and never stop moving.