You'll start off the level in mid-air, with no ground underneath to save you. You will most likely die on your first few lives. To begin, you need to perform a starting air jump. Hold
or press it right after the screen showing the level and your lives goes black.
You'll hit the ceiling and then descend towards the ? block. Right as you land jump again and if done correctly you'll do a long jump. Keep your momentum as you land on the brick, leap up and land on the blooper.
This part is tricky, you need to slow yourself down by just a tiny amount so that you reach the opening in the wall perfectly, otherwise you'll probably hit it too high. If you're too low, well then you weren't moving fast enough.
First thing you want to make sure you are all the way at the end. Run and jump at the second block from the right. Be careful, and time it right, so you don't die by the Giant firestick, or the invisible block there.
Get the mushroom in that block.
Start on the 2nd block from the left, and wait until just before the pirahna plant in front disappears down the pipe. Then run and jump, and land on the center of the falling bar. As soon as you land, jump again, land on the taller pipe, jump again (be aware of the invisible block technology in front of the taller pipe), land on the spring platform, and jump again as the spring platform is moving back up. Keep your momentum and move across to the five-block platform.