In that maze stage ... I think it's stage 4-4 ... where you get to turn things upside down 'n stuff ... I got completely stuck at one point ... and I had to use the Red Pipe thing. I have no idea how to explain it properly ... but it's the screen where there's a top half and a bottom half separated by bricks ... and you see the block with the double arrow that makes the gravity go the opposite way on the bottom half. After hitting that flipping block, you're SUPPOSED to go straight for that door to the right... but instead, I pressed A to go into 3D ... and fell into the space that I came through in the first place and ended up on the top half again. And once I'm in the top half of that screen ... I can't do anything. I was completely helpless. I'm on stage 5-1 at the moment. I'm hooked on trying to get all of those cards.