After Alpha update years ago, it became quite the challenge. However, challenge seems random. Sometimes AC seems impossible at 2300 rating, sometimes 2450 is a joke. Two things create this mess: 1) The ambient spawns are recreated fast, and depend only on the supply cap. What this means is if you pick a team with rifles, commandos, smms, and maybe random assa - you will kill enemies fast, and you will get MORE enemies to replenish the ones you killed. If you pick a team with say 1-2 DPS classes, rest support, u wont be able to kill enemy supply fast enough, so not much will be spawned. 2) The lower the sq rating, the easier it is to kill enemies. Hence you kill them faster, resulting in more enemies. This is why 2400+ Alpha REALLY IS EASIER than 2300+ Alpha. In 2400 you can't kill enemies fast, so the trigger doesn't replenish them. To make calculations fun sq rating determines spawnfactor, that in turn determines randomized number of enemies to spawn. If anyone has a suggestion how we can make challenge translate better to game rating, pls write it.