Wall Clips

The Minus World trick belongs to a wider family: places where Mario briefly overlaps solid geometry instead of stopping against it. A few other well-known ones from the same game:

Corner clips. Jump at just the right angle into the inside corner of two blocks meeting, and for a single frame Mario's bounding box can overlap both before the engine pushes him back out — occasionally far enough to land him on the wrong side.

Pipe-entry misses. Entering a pipe is really "stand in the one-tile column above it and hold down"; get the horizontal alignment off by a pixel or two and you can end up pressed against the pipe's side rather than travelling through it, exposing the same kind of boundary case the Minus World trick relies on.

Underwater clipping. Swimming gives Mario slower, more floaty movement than walking, which is exactly why the World 1-2 wall clip needs water to work at all — the slower approach gives the collision check more frames to catch Mario mid-overlap instead of snapping him back out in one step.

None of these are unique to Super Mario Bros. — any game whose collision detection checks position frame-by-frame rather than continuously has some version of this family of glitch. See The Logic for why that checking method leaves these gaps at all.