1:22:400 H...How???

Simply let Dedede win because the IGT stops once he wins.

Just watch ProfanedGlitch's video

I watched the video a long time ago, but what I don't understand is the programming of DDD. Can you explain it to me?

I don't know much about programming, but here's my guess.

DDD doesn't move faster in this game compared to KSSU, but whenever KIrby gets close to the finish line, it triggers a loading zone which teleports DDD to the end. When you fly to the top left corner at the S-shaped section near the run, and then move to the right (like what ProfanedGlitch did in his video), it triggers the loading zone and tricks the game into thinking you're about to cross the finish line, and so it teleports DDD there.

Ooooooh that makes sense, thanks!