Dead Island Definitive Collection is now available for pre-purchase on Steam. The Definitive Collection includes three games: Dead Island Definitive Edition, Dead Island Riptide Definitive Edition, and the 16-bit styled bonus game Dead Island Retro Revenge.

The Definitive Editions are also available for pre-purchase individually, and they bring the original games to an upgraded version of the engine with new textures and lighting effects, and tweaks for UI consistency between Dead Island and Riptide.

https://www.youtube.com/watch?v=vOdA5VJmgs0
At the base price you get Dead Island Retro Revenge essentially for free through a bundle discount on the Definitive Collection bundle.

As a Steam owner of either the original Dead Island, Dead Island Riptide, or both titles, you’ll also automatically receive a loyalty discount of up to 85% off the respective Definitive Edition of the game(s) you own, as well as a discount on the Definitive Collection bundle based on whether you own one or both!

https://www.youtube.com/watch?v=2fY0PyRlaLs
Store pages for the original Dead Island and Dead Island Riptide will be delisted upon release of the Definitive Editions on May 31, 2016 (to prevent confusion in the future due to slightly similar listings) but for now they will remain active for anyone who still wants to get the originals. Of course, you will always be able to play them if they are in your library!

The loyalty discount will exist for a limited time, but is not tied strictly to the pre-purchase period. If you want to decide later, you can! We’ll communicate ahead of time when the discount runs out. Dead Island Retro Revenge will also be available individually outside of the Definitive Collection bundle at a later point.

Dear Dead Island Riptide players,

These zombies aren't going to bash their own skulls in so we hereby cordially invite you to the closed beta of Dead Island Epidemic! Put your badass zombie bashing skills to good use by grouping up with 3 other players to take down the zombie menace in our PVE horde modes, or see how you stack up against both other players and of course, zombies, in our 3-team PvPvPvE mode, Scavenger!

We've granted you 4 gift copies of the game so you and 3 of your buddies can take part in the zombie madness together!

Features:

Battle Royale: Epidemic's core mode features 3 teams of 12 battling it out in a competition to grab supplies, hold key points, outsmart the competition and blast through hordes of zombies.

Booming Action: You have direct control over your hero. No Last Hitting, mouse-click-to-move nonsense here - it's you, good ol' WASD, and your trigger finger, making it easy to hop in, no muss, no fuss.
No idea what any of that means? No problem. All you need to know is that you need to point your crosshairs towards anyone and anything not on your team!

Craft Deadly Weapons: Fan favorite crafting is here from Dead Island, helping you get the edge (pun intended) on the competition and build an arsenal to suit your playstyle!

So jump in and give it a whirl, be sure to let us know what you think and you can help to shape the future of this game!

Have fun,
your Dead Island team.