We can't edit reviews. Not pretty given the length one can expect them to reach!
If the GOG team are worried about people abusing the editing privilege, why not provide a Wiki-like version history?

Or they could give you only 15-30 minutes (or whatever amount of time) after you finished your review to edit it in case you notice any typos or mistakes. A kind of compromise, so to speak.

OR everyone just could read their posts through even a few times before pressing "Post my message", doesn't sound like too hard of a job to me. Well maybe a 10-15 minutes time to add something you absolutely forgot to mention.

I think the best option would be to allow a preview window of the post before your final submission. That way you can see how it is displayed to others, and format it properly. For the rest, just carefully reading over the post should be sufficient enough. If you forget something, you can always add a comment to your post for those who would like to respond to what you had to say.

You're all talking as if this is a huge, controversial addition...

I was thinking the same thing. I don't really see how the ability to edit your own review is something that can be abused.