2D side-scrolling spin-off Dead Island: Retro Revenge is now available to purchase separately on PS4, Xbox One and PC.
The game had previously been available exclusively as a freebie with Dead Island: Definitive Collection. You can grab it standalone for £3.99.
Whether you want too, though, is a different matter. I gave it a go around the time the Dead Island remasters were originally released and wasn't overly taken by it. Steam user reviews are also fairly mixed.
If you aren't sure what it is, Retro Revenge is essentially an old-school three-lane side-scrolling brawler that has you beating up zombies while on the trail of your missing cat. It's a bit strange, and in my (admittedly brief) experience, doesn't seem particularly good.
Anyway, if you want to check it out, head to Xbox One, PlayStation Store and Steam to give it a download.
Source: xbox.com, store.playstation.com, store.steampowered.com