About Twinkle Park with Amy...
There are actually 2 shortcuts on Twinkle Park. The first one (which is the one I use for my 50.96 sec time), is right after you enter the castle. As you enter the castle from the first part, try to be on the left hand side and jump into the castle so you'll be in the air when you enter. When it switches to the inside, hold forward for a split second. Then as you land, press the stick down-right and jump towards the door (what you are aiming for is the corner of the door where it meets the wall. If you are facing the door from the inside of the castle it's the lower left hand corner). The timing needs to be perfect. You need to hit the bottom corner and do a hammer jump just as you hit the ground. If you did it right, you'll glitch through the door. Now if you just hold that direction, you'll still cut through a bit of the castle and land in a room, but for maximum distance what you want to do is as soon as you go through the door, rotate the stick counter clockwise and when you land you should land near the beginning of the second to last room (which is the one with the mirrors, spiked balls that drop, trap doors and steps that go up). From there, it's a piece of cake to the end.
Now the other one is very difficult. I have never done it, nor seen it done, but have talked to several people that have done it. And according to them, this is how it's done: At the start of the level, jump forward once then jump back towards the gate behind you and just like you did with the door glitch, do the exact same thing on the gate (I'm talking about the gate that is right behind you when the level starts). Except you need to hit the RIGHT corner and not the left. Then, if the timing is perfect, you should hammer jump up and over the wall and land on the slope leading directly up to the balloon. Theoretically it should work on the Gamecube version (they all did it on the Dreamcast version) according to them. But I have not heard of anyone doing it on the GC version. There are a few shortcuts that were in the DC version that they excluded or 'fixed' for the Gamecube version.
Good luck. Please let me know how you all are doing on the level. It's one of my favorites and one I play the most.
Dave Cramer