Fallout 1 is getting an unofficial remake within Fallout 4 with an "overhauled leveling system" and all its classic quests, and its demo is finally available

gamesradar.com:

A fan-made Fallout 1 remake is in the works within Fallout 4, and a demo is available to try out right now. 

The project, which has been in the works since February 2021, is called Fallout: Vault 13, and it works as a total conversion mod for Fallout 4. It'll eventually feature five open-world areas, including familiar locations like Shady Sands, the Khan Base, and unsurprisingly, Vault 13 itself. 

The devs are going all out, creating a "completely overhauled leveling system that mirrors the original game's complexity and depth," and the "classic traits, perks, and skills system" from Fallout 1 are all being reintroduced, too. Some perks are even being "redesigned to take advantage of the potential of the 3D space." On top of that, it was previously confirmed that all quests, areas and NPCs will eventually be included, complete with "some tasteful, lore-friendly additions."

Of course, the demo offers just a taste of what's to come – the devs have released it now so that they can gather feedback ahead of the final release. For now, you'll only be able to explore one of those open-world areas – The Inyo – and there are a handful of other differences between the full version and the demo, too. Currently, there's no voice acting despite it being planned for the final release, your skills won't automatically adjust when your SPECIAL stats change, and when creating your character, selecting the 'body' option will make them disappear from view. These things are all temporary blips, though – they'll all be ironed out by the time that full release comes around.

If you want to dive in on PC, there are a few requirements you'll have to fulfill first. First of all, you'll need to own all of Fallout 4's DLC, and remove any Creation Club content you might have in your data folder. Crucially, you'll also need the Fallout 4 Script Extender, and you must downgrade to the pre-next-gen update 1.10.163 version of the game – the mod's devs have linked to instructions on how to do so on