I know I’m late to the party but I just found out and didn’t find a post regarding this
TL;DR: Steam now calculates review scores based on reviews made on your languages only (if enough). This is on by default, but can be reverted to go back to review scores based on all reviews (from people that purchased the game directly on Steam only)
I kinda hope they also weight reviews based in hours in the game. If ten people with 1000 hours I’m a fame recommend and 1000 people with <10 hours don’t recommend, I really hope the score is better than 50%.
Well maybe they stopped playing the game because they didn’t like it? I don’t continue to play games I dislike