Having tried it, there's no way the size of this download is justified by the level of content... The graphics are no better than any other UE4 starter project. There's an awkward mix of very low resolution textures on large, obvious objects and ultra high-res textures on small, insignificant ones. But the game seems like it's trying to cover that over by using every single post-process effect cranked up to 11.
The writing is average I guess, but it's made worse by the bad translation. There are some really cringy lines that I suspect are common Russian turns of phrase which have been translated directly into English, instead of translating their intent. Overall the experience is just a linear walk between a series of splash screens. First these screens are the tutorial, then they become exposition.
Really size matters though. If you compare WL with other UE4 projects like Wild Life, Breeders of the Nephlym, Sinful Empire or Fallen Doll, they all offer a lot more content (and more interesting content) for only 1-2gb each... White Light is a huge download without a huge game to back it up. It's unpolished and unoptimised to the extent that I suspect the download contains a lot of assets which aren't even being used... If it were only a 1gb download it might be worth keeping an eye on each new update, but I probably won't check back in until it's either finished or a gets an optimized build.
(If you're on restrictive download limits this should be a hard-pass. I'm on 60gb/m and definitely regret it.)