Dead Island: Epidemic is entering closed beta, and registration has officially begun. We really haven't heard much about Deep Silver's zombie-themed MOBA since August of last year, but the game is obviously progressing. Participants will be taking part the "final stages of development," and join the existing Alpha testers community.
30,000 Alpha testers have already had a go at Epidemic, and closed beta testers will be joining them as some of the first to try it. That said, signing up right now apparently allows you to play before closed beta officially starts. You'll also get exclusive in-game items and other rewards that cross over into the full game.
Deep Silver's Isaac Parakhen stated that the game has received "outstanding feedback" from testers so far.
Deep Silver: Epidemic was announced in August 2013, as a free-to-play zombie MOBA (dubbed "ZOMBA") based on the Dead Island survival action series. The official site has been revamped since then, so be sure to check it out -- especially if you're hoping to register for closed beta.