Survival mode is epic. If you have no idea what it's like to listen to three of your best friends screaming into their mics for help, you're missing out. We attempted an ammo run and ended up being too slow to get back to our defensive position, so had to punch through everything with melee fatigue (systematically, as we do: me, adam, gavin, conor and then back to me - you just listen for the sound 3 times then clear as much as you can :D)
Anyway, we finally punched through a horde, two or three hunters and a smoker that kept pulling us and found two tanks where our defense used to be. Luckily I had pills which I through to conor because he was most beat up (which is ironic because he'd never be beaten up in anything but a game, even during an apocalypse) and me and him managed to survive by throwing a molotov (tank) and pipe bomb (horde) and running.
After this we had no defence or plan, it was just us running and looking for stuff to let us last longer and screaming when we found a tank or other zombie suddenly upon us. Very much fun was had and eventually, when the melee system failed we got torn apart by two tanks and lots of stuff. It's cool how tanks save you from smokers and hunters though :D
My only complaint is the lack of witches. It would be cool once you get past 10 minutes or so if one or two riled (nerf-version) witches came sprinting at you periodically. Would add to the "AHHHH - MICHAEL. OH GOD GET IT- THANKS. SHOOT SHOOOOOOT MELEE <high pitched scream> *silence* damn." factor I've been enjoying so far.
But goddamn adam leaves us for dead too much
TL;DR: get three friends to get this game, plop them in survival mode and screamlol.
