I won't comment on the plot/characters (because everyone else has said what I wanted to say), but I am in love with the set/costume/art design, from the MC Escher-inspired stairs to the extravagant room for the VIPs (although the actors for them was a poor choice).
The only thing that really irked me was the blood splatters, they weren't lit accordingly to the scene and didn't cast a shadow too lol