warm pond
Crate capture: crates spawn spawn in 2 minute waves, so if you capture all crates in 1 minute you're left with another minute of waiting in spawn and shooting the occasional zombies.
Eradication surge: zombies come in waves of 70-300 zombies depending on the lobby level and how late you're in the match, however because the mission only finishes when the timer is out, the best strategy is to intentionally stall every wave by not killing the last zombie.
I see two approaches to fixing this:
- Finishing the objective advances your progress, so in eradication surge the match will end when the goal is reached, and in crate capture the next wave of crates will appear shortly after the one before it.
- Keep the time limit but increase the rewards in accordance of the player's performance, the more zombies you kill or crates you capture past the goal the more you will be rewarded.