Before going on, please make sure that you possess 1 red key, 1 dark blue key, 2 light blue key, 3 pink keys, 3 green key, and 2 yellow keys.
When you arrive in the room, you can stab the oncoming Witch if you choose. Head left and collect the yellow and light blue keys, and enter through the yellow door.
This is another room that takes quite a bit of set up in order to proceed. The first goal is to unlock the doors surrounding the pulley block so that you can begin moving it. Start out by jumping to the left side of the block that is directly beneath the light blue door. Push it to the right just one-half of a block width so that it hangs over the edge of the platform. Then head over to the small elevator, ride it up, and jump from the top of the lift to the platform above. Push the block to the left of the yellow door one-half of a block width to the right so that you can reach and unlock the yellow door. Do so, then continue to push the block to the right. Continue to push the block until it is between the blocks above and below it. Then push the top block over to the left so that you can reach and unlock the light blue door. Your final block configuration should look like the picture to the right.
The next step is to step up the blocks in the room to create a bridge for the pulley block so that you can ultimately get the pulley block to operate the lift. To start, you can set up two of the blocks that you just manipulated to free the pulley block so that they fall to the floor. That will create one of the three bases upon which the bridge will be built. The other two bases are already on the floor to the left. Set the right floor block up by placing it squarely in the middle of the middle gap, and set the left floor block up by pushing it anywhere under the left gap. Then begin pushing the remaining blocks into place so that a bridge is created across the ledge above the floor. You will need to use the remaining block at the top to fill in the bridge before you can push the last block into place on the left. Once the bridge is complete, push the pulley block down to that level and push it across the bridge to the elevator. When the pulley block is on the elevator, jump on top of it and ride the block up. You must jump on it rather quickly. If you are too slow, you may lose the block, or get squashed as the elevator rises. When you can, get off to the left, and push the block to the right so that it connects with the pulley ropes. Then get to the other side of the block, and push it to the left so that the elevator rises and moves out of the way of the dark blue door. Once the way is clear, enter the dark blue door.
You must jump immediately when you enter this room. Stand next to the conveyor belt and jump up so that the jar lands beneath you. Then jump off the jar to the ledge above. You will end up on a conveyor belt directly below a series of spikes. You must make small jumps to progress left along the belt, but remain below the spikes. You must also carefully land to the right of the spikes. Then walk along to the left when the barrier is vibrating and open the pink door. Ride the right elevator to the platform above, and very carefully jump over the Devil Flower in order to collect the dark blue key at the end. After you collect it, you must jump off the block next to the elevator and over to the spikes on the left side to take the left elevator to the room above.
After you arrive, jump up to the pink door and open it. You can head to the right and collect the money bags and extra life potion. Then wait for the barrier overhead to freeze, and jump up to the small elevator on the left. Ride it up to the room above.
Carefully jump between the spikes to the right, and over to the barrier above the yellow keys. When the barrier stops, drop down and collect the keys, and jump back out. Jump up to the ledge with the jar, and push the jar aside, but just enough to use it as a platform to reach the (right) elevator above. Ride the elevator to the top.
Jump up and around and drop down to collect the yellow and light blue keys. Then hop back up and cross over to the right side of the room. Drop down the gap to the section below with the three yellow keys and three light blue keys. You can collect either one first. If you collect the yellow keys first, you can safely jump back up to the ledge above the yellow door. When you collect the light blue keys, you'll have to drop back down to the room below and make your way back up to this room via the same elevator. Once you have collected all of the keys, jump over to the gap in the wall on the right by jumping from the ledge above the yellow door.
This room starts a fast sequence of room switches while you take advantage of the invulnerability that the Power Light is about to grant you. First you must deal with the Fighter that guards the green door. Don't move, just continue to jump until the Fighter plunges off the platform. Then open the green door and collect the dark blue key inside. Hop up and bath in the Power Light and let it bestow invulnerability upon on. Then drop down through the gap between the spikes. You must make it to Step 57 before the effect of the Power Light runs out.
Continue to fall, and collect the extra life potion on the way down. Head to the left.
Drop down the gap in the floor.
Continue to fall and enter the lower gap in the right wall.
Proceed to the right, hoping over the spikes and the water, and over to the set of moving platforms. You must navigate the platforms in order to reach the green door above. Remember that you have to actually move with the platforms in order to stay on them.
You should still have your invulnerability from the Power Light earlier. If you do, feel free to fall down from the ledge and land right on top of the spike to the left of the oxygen tank. Then jump over to the ledge to the right of the oxygen tank and ride the elevator to the room above. If your invulnerability ran out, don't despair. Collect the oxygen tank and drop into the water. Climb out of the water on the right side, and drop down to the room below. From there, jump over to the small elevator on the far left side and ride it back up to this room. Then jump up the ledges and jump over the spike and up to the small elevator on the right to proceed.
Collect the rings for points if you wish. Then collect the yellow and light blue keys. Stand in the Power Light again to renew your invulnerability. Then jump through the spikes to the right (collect the extra life potion above if you wish) and fall down the gap in the floor.
As you fall, push to the left to reach the extra life potion in the wall. Then jump across to the right and open the very top yellow door.
Walk up and around to the chute on the right, and drop down to the ledge. Then very carefully jump over the pit containing the Fighter, in order to reach the second yellow door from the bottom.
Drop down and collect the two pink keys. Then open the bottom yellow door.
Walk down the alley to the elevator, and ride it to the ledge above. Open and pass through the top light blue door.
Drop down to the floor below. You should still have a good deal of invulnerability left, so jump up to the ledge patrolled by the Bishop, and simply walk through him. Jump up to the small elevator above, and ride it up to the room above.
By the time you reach this room, your invulnerability will probably have worn off. So quickly jump over the Bishop that approaches you and on top of the barrel. Jump up to the ledge to the right. Then jump up to the ledge above that one, and open the light blue door in the middle. Collect the light blue keys and open the top yellow door.
Start out by riding the floating platform to your right. As hard as you try, you will be unable to leap over the Devil Flowers and manage to land on the upper platform beyond. Instead, jump over the high Devil Flowers and land on the right edge of the lower Devil Flower platform. Then wait for the next floating platform to arrive and travel with it to the bottom yellow door. Open it and proceed through.
Leap over all the gaps, small and large, and proceed to the opposite side of the room. Open the bottom light blue door.
This room is more tedious than difficult. You need to get two of the bricks over to the pink door on the right. Head to the right side of the pulley block and push it over to the left. Push it just far enough so that you can push the brick over to the right, past the elevators and over the barrier, so that it fall down into the pit below. However, you should not attempt to push the bricks over the barrier if, at any time, the barrier will freeze while you are pushing the brick across. If it does, the brick will fall down and become stuck, and you will have to reset the room and start over. Careful and patient timing is required. When the first brick has been pushed across, jump back up and push the pulley block back to the right. Load up the left brick onto the lift, and repeat the process. Once two blocks are down, push the top block to the right, and open the pink door.
Drop down to the floor below, but be very careful to monitor the position of the Bishop. Avoiding the Bishop, make your way over to the small elevator on the right. Use the elevator to reach the higher ledge on the left, jump over to the green door ledge, then back over to the left, and up to the ledge in front of the yellow door. Open the yellow door and proceed through.
Be careful of the Fighters here. Either cause them to jump off, or be prepared to stab them as they approach you. Collect the yellow key, and jump into the middle alley and make your way to the small elevator. Ride it up to the room above.