Mechtropolis

Mechtropolis resembles an urban city at nighttime. It is the last/penultimate world depending on how you view it, as Null, World 9, is the win area.

Mechtropolis has turrets, which spin around, making a full cycle once every 10(?) seconds. It spits out bullets equivalent to Rapid Fire Droids. It can not be damaged/killed, however it will disable after you complete the room.