The finale concept is the same in each campaign—after you reach the rendezvous point, a rescue vehicle picks you up and takes you to safety. The only problem is that you have to wait for the rescue vehicle to show up. Needless to say an incredible onslaught of zombies do everything they can to kill you while you wait.
If you ever play one of these finale's you will know that surviving at all is hard, but surviving with no one taking damage is impossible. It requires a well laid out plan and it requires everyone on the team to work together and to stick to the plan, but improvising when necessary. We were determined to do it.
We leveraged every advantage we possibly could. We set the difficulty to easy, and we found a rock out in the ocean that for some glitchy reason zombies can't seem to climb but we can (its a known bug that someday will get fixed I'm sure). The only danger is the 'tank' zombies that throw rocks at us and the 'smoker' zombies that try to yank us off the rock with their incredibly long tongues that they use as a lasso rope.
Finally, when the rescue boat comes to pick us up we have to leave our rock and run to the dock, where a nasty 'hunter' zombie is always waiting for us. These guys leap through the air and tackle you. You can melee them while they are leaping to block them, but the timing and angle has to be precise.
Well, at 2am last night we finally got the achievement!
You may think it was a hollow victory as we did it on 'easy' and we exploited a known bug, but at 2am in the morning when we all jumped onto the getaway tugboat with our hearts beating fast and dreadful concerns that someone took friendly fire at the last moment, we were all elated when we got the achievement.
Next, we will attempt to make it through an entire campaign with out any 'boomer' zombies vomiting on us.
This game only has 4 campaigns, but when you can get a good group of people to play with, it never gets old.