Rooftop is a secret floor that the elevator is on the roof of the building where the players are located, on which there is a sign containing some kind of message from the developers (usually Milo). Near the sign there is a spherical object and a structure resembling an antenna. You will also receive the Rooftop badge for visiting this floor.
In the Christmas version, the floor is covered with snow, and the sign is decorated with several gifts. Also next to the sign is a decorated Christmas tree and presumably Santa Claus, and a sleigh is located at the back of the floor.
Previously, there was a small chance that instead of a message, a photo of the Illuminati symbol would appear on the sign.
This floor has a 76 in 20,000 chance to appear (previously 9 in 20000).
In the Halloween version, the sign on this floor is surrounded by pumpkins, and there are 2 boxes in the back.