Skimmed the video to see what the ruckus is all about.
I really like aspects of the visual style: obviously the baddies, the ugly carpet design, all the lights, fountain, the overall tackiness (clearly intentional), the room with the broken security cameras
Theres no denying that the overall reaction to this world is mixed. I think it's way exaggeratedly negative ... its like people are looking for an excuse to compare this to Mighty No 9, or "ugly unity games." Yet, I agree something is "off" -- the proportions are exaggerated. The slot machine part takes me out of it a bit, it's so tiny compared to even the floor boards beneath. In a way the giant central area feels like pyramid level in scope, skinned with casino textures/assets, all placed in an enormous room.
Really, though I highly doubt I'll be complaining while exploring this level. The gameplay looks pretty fun