Prowler posted:

It's just slight of hand. There are two doors, one is hidden by the very out-of-place bullet bill blaster. Either one blaster spawns or the other spawns. What you're hearing is a bomb blowing up a hard tile, which allows the screen to scroll differently (and give the appearance that the door is in the same position).

All of the gimmicky setups you find in popular easy and normal are usually just level scroll shenanigans or spawn manipulation (actual glitch levels--even "tech" levels, don't last long because they get reported).

I feel personally vindicated that I figured it out the second I saw it, but, full disclosure, I checked a level viewer just to make sure I wasn't full of poo poo, lol:

https://smm2.wizul.us/smm2/course/G8X-0NN-CKF


I've seen several hundred hours in the editor. I can usually answer questions about weird level building tricks, but not gameplay tech (e.g. advanced shell stuff like clams and donkers). Edit: or puzzles like that one up there, geez.