The bridge is really ugly. You need to flip the levers and see what will happen. Every time you see a way further you must try, which levers will allow you get even further. This includes all levers, which are accessible currently (where you can jump over the holes in the bridge). It will often happen that you find too late that the way you decided for a long time ago was a
wrong way. Ueee. :1pissed:
IIRC, you can find the right ordering of flipping the levers in the Best Tips thread. It consists of 14 or so steps. You need to follow the directions exactly.
Before you lose your nerves completely and remove the game from your disks, return to the beginning of the "puzzle", when all blocks of the bridges were down. Jump into the water and swim to the north part of the bridges (I think it is north, the way directly forward from the start of the bridges). You can "jump from the water" to the lowered blocks of the bridge there. Now, go to the end of the bridge and "climb a chain" there. That means: (a) Go to the chain (it does not matter wheter it is the chain to your left or to your right) as close as possible. (b) Look up as much as possible but look a bit forward, too. Check with the "forward" arrow, you should not retreat from the chain with forward arrow pressed. (c) Press "run" and "forward" together and now start pressing "jump" (yes, you have three keystrokes pressed righ now) repeatedly. You will "jump-run" along the chain, that means you will climb
(d) Once you reach the exit (above you) make a step aside. You have reached the exit from the north bridge. It needs a bit of skill but once you get skilled, it's very easy
Finally, flip all three levers there.
All blocks of the bridges will go up. No holes on your way any more. No need for "backtracking" the terrible levers. Return back to the start of the bridges (using the bridges, not the water) and continue.