I want to post a scratch project on codereview for people to give feedback at, but im worried that it would get downvoted and flagged for being off topic.
So are scratch projects allowed? And if not, why?
There's no rule against code that is not in textual format. The only tricky rule to comply with is the requirement to embed the code directly in the question itself. If you use the image Stack Exchange imgur hosting service, I think that should satisfy the requirement.
Don't see why Scratch wouldn't be allowed. Go for it.