Hello,
this is kinda a request to gog team,

It would be nice to update our review as the reviewed game evolves
(maybe the dev will fix what is gamebreaking :) )

just an idea :)

There are various wishlist entries for this, for example:
https://www.gog.com/wishlist/site/edit_reviews

Updating reviews after it's been published is a tricky thing, ethics-wise. What if I write an honest review of a terrible game only to edit it into "omg purrfect!! bestest gaem evar!11!!" after the initial review gets enough upvotes? We don't have enough data science + community oversight to prevent that. I think pestering blues is as good as a simple system is ever going to get.