Zombie Apocalypse: Never Die Alone

This has to be done in Single Player mode. When you finish the last level, (Level 10) after the credits, the achievements will pop.

Some tips to make this easier for you:
-The more you level up your characters, the easier it will be to make to the end of the stage.
-After you beat the level boss (the fisherman), the game isn't quite over. The credits will roll. After that, the achievment will pop (that's when it popped for me).
-Use your pwnage and Bait will abilities wisely. I saved the pwnage abilities for the damned zombies and for the boss and used the baits for the common enemeies.
-There are 5 weapons around the stage that spawn after a certain amount of time has passed. The gernade launcher is available start of the match, bottom of stage. The modified flare gun is the last one to spawn.
-This stage takes between 10-15 minutes to finish, so make sure you have at least that much time for this achievement.
-Switch characters when the need arises and keep everyone alive. More firepower will help in the long run.
-Have fun! :)