Dead Island Definitive Edition will release later this month, bundling the original game with Dead Island: Riptide and another, more pixellated outing that we haven't heard much about, until now. Turns out Dead Island Retro Revenge is a 16-bit styled side-scrolling brawler with lots of flashing colours starring a very angry man, who is eager to get revenge against zombies for some reason.
The angry man also appears in the below trailer, which serves to describe what Dead Island Retro Revenge is, in addition to providing some (quite scant) narrative context. Exacting revenge on someone implies that a knowingly bad deed was committed, but I doubt zombies are sentient enough to do anything knowingly. Based on that, and the general attitude of the angry man in the trailer, I can only guess that he's mad.
Still, it doesn't matter how mad he is if he's simply a vehicle for killing more zombies. Dead Island Retro Revenge will be available with the Definitive Edition on May 31.