For those who never owned DI stuff - that's not bad. For those who owned the DI stuff, we could've gotten those two Definitive Editions at $3 each before June 20th via Steam.
I have played fully through Dead Island [original] + DI: Riptide [original]. If you want a first-person game that's mostly melee-based & you smash zombies in cool paradise-resort of an open-world, you can't really do too much better than the DI games. It's basically an inverted Borderlands: a ARPG stuck in first-person, but where you kill zombies and use melee weapons. Though, you'll constantly be breaking weapons; upgrading weapons; and taking on fetch quests (kill X enemies, go to X area, find X things, etc).
Riptide is more of the same - but if you like Dead Island [base], that shouldn't be a problem. It also has the new defense mission type here - which the series really did need something of that sort. Plus, you can also take your DI character + import it right into Riptide.
Don't expect a spectacular story, character development, or anything of that sort. This game series ain't focused on that.
The only part of DI that focuses very strongly on story is Ryder White DLC & you can't even level Ryder up in that episode. It's all straight-up action + story, mostly. Fill in a lot of the blanks and odd questions you might've had about the original DI, in which some things felt pulled-out of its butt, left untold/unexplained, or whatever else you can think of. When Techland actually tries (i.e. see Ryder White DLC + Call of Juarez original game), they can tell a story - but, I think for DI series, for the most part, they just decided for the most part not to try much + just stick to mostly gameplay.
I ain't done much w/ the DI Definitive + Riptide Definitive remasters - but, DI Definitive flat-out looks much better than the older editions. No comparison. There's tons of new graphical bells + whistles stuff in those, which weren't in the original editions & some better textures are being used here.