I used to play it quite often, I stopped after one of the updates. It was the one after they released the M4 and the IED and added the 4th character and ruined my favourite map cinema
. And basically because L4D is my go-to zombie game, L4D and ZPS are two completely different games, L4D you have to keep moving up to new checkpoints, and where as ZPS you have to find a good spot to barracade and stay alive for good period of time. Overall it's an ok game in my opinion. PS I'll try to play more often with you Shippo