引用自 FiskyOwO：

Proof: https://imgur.com/a/6OFFLjc

My thoughts: Flakk's tight and restrictive trenches and bunkers force the player to use the central mound where the Pack-a-Punch machine is to train. The most threatening things on higher rounds are accidentally getting stuck on an object and avoiding spawning zombies. The smallness of the mound and the zombies climbing up the sides/rising from the ground makes it extremely good practice for training hordes and avoiding both objects and new spawns.

What's your highest round on this map?