MC has 4 different locations around the city (including one in Pudong!), and is quite cheap, at a measly 100-200rmb per person. Consequently, it's on the janky side: a fair number of puzzles involve peeling print-outs glued onto surfaces and rooms have "bookshelves" made of low resolution posters, but the physical puzzles are decently put-together. If there're a lot of people waiting, there's a good chance they'll team you up with another group to reach 8 per room.