This is a fun resource for doing a bit of research on level design: http://www.nesmaps.com/maps/SuperMarioBrothers3/SuperMarioBrothers3.html
It displays the entire maps for each of the levels in SMB 3, giving an idea of how Nintendo's designers approach building a level, create nice aesthetics, handle pacing, and, also, illustrate how short a lot of the levels in the game are.
It displays the entire maps for each of the levels in SMB 3, giving an idea of how Nintendo's designers approach building a level, create nice aesthetics, handle pacing, and, also, illustrate how short a lot of the levels in the game are.