Back in April was a Steam Community posting about Dead Island for Linux, to which one of the game's developers responded, "There might be Linux support in the future. However we are developing the game for Windows PC first. It's probably going to be post-beta."
There's been signs of Linux work for Dead Island in recent days via the game's SteamDB entry and several Phoronix readers have written in to report that Dead Island is appearing on their Steam list of Linux games.
Phoronix readers started this thread today with it showing up in user's Steam libraries but it doesn't appear to be working quite yet with missing the Linux game executable.
Here's to hoping that it's coming very soon, but until then, it does appear to run fine in Wine per the WineHQ AppDB entry. Dead Island starts out at $20 USD and can be found on Steam.