At least say what exactly is not good. Like imagine a random person(me) looking at comments to see the critique, thinking if it's worth it to play or not. Pictures - that random person can see on his own, they're in the original post and he already doesn't mind them, so he starts looking at what other people say.
And then he sees "It's not good". What..? What isn't good...? Art, gameplay, writing, scene ideas? Clearly not all of it, since you also say you see potential. In addition, for the dev it would most likely be impossible to improve "notgoodness" into "goodness", so it'll only leave him guessing, instead of answering the problem. This will not lead to any progress, it's irresponsible, and YOU will lead the dev to stagnation. No, you basically lead the whole society to it, being a part of the whole machine of irresponsible critique. Just writing a comment like that you're damaging our civilization. You're sinning. Condemning your soul, and the souls of everyone around. Don't send us all burn in Hell - elaborate..