1. You drop into a crawlspace. If you head right you'll fall to your death.
2. Head left too quickly, though, and you'll be fried by a burst of steam. Roll left just enough to trigger the steam, then wait for it to stop before advancing.
3. You'll drop to the next level where you must pause for another burst of steam.
4. You'll drop to this "T" junction where steam is pulsing to your left and right. Wait for the steam on the right to pause and then advance.
5. You'll emerge at this junction where, mercifully, you can advance in either direction to successfully exit the maze.
6. Drop below then enter this chamber on the left to recharge your gun.
7. Destroy the three barriers on the right.
8. Advance right two frames to take out this guard. Continue right.
9. Stand close to the ledge then jump.
11. You'll land safely on this ledge, rather than on the stalagmites below. Shoot the rock face to create an opening.
12. You're now in a large series of tunnels which comprise one of my all-time favorite puzzles. You can explore the area a bit if you like, but since you're reading this you've probably already exhausted your patience and just want to get on with it. Start by dropping down this shaft.
13. Drop to this position, then jump across the next shaft ahead. Note what appears to be a plugged-up shaft behind Lester in this shot.