Link: http://www.greenmangaming.com/games/action/dead-island/
Use the 20% off voucher SUNNY-SAVER-20PEC to bring the final price to $33.96
The game uses Steamworks so it can only be played through Steam.
People who pre-order will also get the pre-order DLC for free:
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Blood Bath DLC Features:
4 deadly and hazardous Arenas with endless waves of zombies
Play in single or co-op multiplayer!
Loot XP and items and bring them over into your campaign
Leaderboard to challenge your friends
New gruesome weapon: Sonic Pulse Grenade