This is fairly easy to get, but if you're like me and pretty much suck at the combat in Dead Island, here's some tips for you:
- Before you go into the arena, buy a large med pack off the guy standing next to the workbench - chances are you won't need it, and a lot of the zombies will drop medium med packs in the arena anyway...but, better safe than sorry.
- Choose Arena A (easiest)
- When you enter the arena, choose "fists" from your weapon wheel and then head to the left. You'll see a narrow bridge on the right. When you get to the bridge, look to your left and you'll see a work bench. I would recommend setting yourself up here with your back towards bench so you can still see the bridge as well as the path you just came up. The first few waves are easy. There are only 4 low-level zombies in Wave 1 (I was at Level 34 and was able to take out them out with just one kick each). There are about 15 zombies each in Waves 4 and 5, so at this point I would recommend backing in closer towards the bench and staying away from the bridge area - simply because when all the zombies start rushing at you, all it takes is one to get through and land a punch that sends you toppling over the edge.
- I would also recommend focusing more on kicking and stomping (with LB) than punching (with L/R triggers). Waaay more effective.
In between waves, hit your B button to use a med pack if you need it and be sure to loot the bodies for more cash and med packs as well. I had 7 med packs going into Wave 5 (and that was even after topping up my health in between each wave) so even if you are crappy at combat you shouldn't have too much of a problem keeping yourself alive long enough to nab this achievement.