One at the top that goes outside to the circular area. Another at the bottom in to a little circular room. The other two go into a large rectangular room that leads to the other side of the outside circular area and also has a side door to the little circular room. Pills and rockets are all over the staircase. Dogfights take place in the rectangular room and the small circular room.
Rails fly from each entrance to the outside area.
If you rocketjump into the windows on the upper level, the player finds himself walking on air in a room with invisible walls. The central room has four doors. One that leads to a sewer tunnel, a door that leads to a T-tunnel, a door at the bottom that leads to an inner area, and a secret door that leads to the upper floor of the inner area. The sewer leads to an outside area which can also be entered from the T-tunnel. There is a tall satellite in the middle as well as a camping spot for rocketjumpers.