Constant Cave Ins: There are actually 2 strats, that save different amounts of time. The fastest requires two very precise jumps. The first being a double jump forward dashin order to land in the black ceiling section early, and then you skip one more cycle by jumping in between the green and pink ceilings. Saves 7 seconds. If that's too hard for you, there is an easier strat. You play the level regularly, until the black ceiling. At which point, you don't stop, and just run to the end. (You should end up safe under the green ceiling.) Saves 5 seconds.

Gotta Go Fast: If you get every speed boost on this level, it's possible to die, and in most cases you go too fast to land directly on the trophy. Both can be avoided by jumping right after you leave the final ledge. Saves less than a second.

Pain Train: I found a really consistent way to beat this one fast. As long as you time your jumps, you can get to the first colored platform without using your upwards attack (to avoid lag). This allows you to do a phantom jump (jumping right as a platform disappears) on the green platform at the start. Play normally until you land on the next yellow platform, and once you do, immediately start holding right, and doing double jump up attacks, getting as much distance as you can. I promise that platforms will appear underneath you. Do not turn back. Can't be sure how much time this saves.