Personally, one of my favourite games of the 90s was the original Rayman - a 2D platformer starting a 'man' with no limbs and floating hands/feet for whatever reason. It debuted on the Sony PlayStation - but a prototype for a SNES version was coming along nicely before it was ultimately shelved.
During the great Beyond Good & Evil 2 tease of 2016, Michel Ancel - who yes, created Rayman too - found a working copy of this prototype long thought to be lost. It might not be the one of the later builds, but it was something that showed great promise.
Since finding the copy last year, you can imagine how many players video game preservationists would have wanted to get their hands on it. Thankfully, with Ancel's blessing, Omar Cornut of Wonder Boy: The Dragon's Trap developer Lizardcube - was allowed to upload the early prototype build for all to enjoy.
Picking it up through DropBox and sliding the file into your SNES emulator of choice is basically all you need to do to embrace 20+ years of video game history. Being regarded as a classic to this day, it's a shame the charms of Rayman weren't available to those Nintendo enthusiasts until the Gameboy Advance port in the early-mid 2000s.
It's incredibly brief and seemingly void of the music that practically composed the gameplay; but it's something for the history books at least. It's just a shame they couldn't have gone with a more colourful level at first.