oof ruined the run a lil bit but oh well, but can someone still explain what even happened? i had like, no special genie code or anything turned on, just plain smb1 in FCEUX 2.2.3

This is the wacko collision detection of SMB. I mean, what do you expect from a game made 33 years ago. Another example of this is in the coin heaven in 2-1, you can just pass right thru the platform at some points. It also may have been that the platform was moving very fast, and that the game has no frames to counter for his falling speed. For more info, go to this resource: http://tasvideos.org/GameResources/NES/SuperMarioBros.html#FirebarHidingTrick

Make sure you're using an accurate rom. I've never ran into a problem like this but the hit detection is sometimes wonky in this game.

@Mars02 I believe he is using a PAL ROM, which acts like this with the platforms and how they manipulate subpixels. Watch happylee's TAS, he exploits this characteristic in 1-2.

@iplaymario124 it's not a pal rom because the tempo in the music on the video is the same for the ntsc version.

it's not PAL, it's ntsc im pretty sure.

Yeah, Elevators work in strange ways. If you look at Kosmic's Warpless WR, in 3-3 you can jump through a platform. It's essentially what happened here, except you were moving downward (which is actually a lot rarer, but possible).

For me, the video has no sound (Actually, the sound is just extremely quiet.). Frame advancing the video makes it look PAL.