Oh man that is so annoying (the non-directional sound in the classic maps)
I've had a monkey in Ascension get trapped under the stairs between where Mule Kick is now and Speed Cola. Took us a while to find him. Gave us a nice little break.
The first time we did the EE on Moon, we got to 29 and had left a crawler before teleporting to Earth and when we came back we could not find the zombie ANYWHERE - plus the round number had disappeared from the bottom left corner. After some time, we all dolphin dove off the cliff at spawn. It was pretty lame. That was on XBOX (I only play on my XBOX when the maps first come out until they're out on PS3).