Criticism is fine as long as you remain respectful and don't offend any of the content creators etc. i believe.
I don't think I made myself clear enough.
I'm trying to say that it's part of the process of producing a game to accept criticism made by testers. Games have entire departments of testers that look for bugs, try to break the game, and comment on the playability/usability. Game testing databases have whole categories for criticism. If something is UV-mapped incorrectly and visually jarring, you had better make a report on it, even if it might hurt the artist's feelings. If you experienced a bug that makes continuation impossible because you don't receive an item or game state that allows progress, you
need to make a bug report tagged as severe. If something is just plain not fun (and not due to bugs), you report that in the category for flaws in design. Something being "not fun" in a game will kill its success, so it's important to have testers there to determine whether it's worth being played by actual players.
I've heard numerous times from industry professionals that "If you take offense to criticism, you should not be making games." Criticism is
not belittling someone personally. It's the judgment of concept, process, or execution. If you can't accept criticism, your game will fail.