The dungeon design is aweful imo, so I could definetly see someone rating it down a lot for it.
I forgive it a lot, and I'd give it a 9. IMO it's still good enough even though I think the dungeon parts are really really lazily designed. They're still fun because the battle system is good enough. That's my justification atleast.
I also review less harsh than kupohead, if you look at my profile My AVG is 6.5.
I justify that in that I avoid the really bad games so my AVG would go down to 5.5 if I played more of those really bad games, that I avoid.