Entering the first door on the right, a bit down the stairs, is this room. Halfay down these stairs is a target in the ceiling. Shoot for a secret door, and a power-up.

Just a few steps further down (you can see the door leading to #1 left) is this room. Shoot the smooth bit of wall.

In the room outside the slipgate, shoot the yellow light in the ceiling. Goddie await.

Outdoors, under the bridge, spot the target. When hit, it opens a door to a goodie room.

Right next to the exit slipgate, the top of a box holds a target. Hit it, some steps appear. Climb to the top and jump down behind the slipgate.