Welcome to the community! This TAS is very improvable, and I'll list most of the areas it can be improved a lot.
In 1-1, it is possible to get a faster underground section, plus a flagpole glitch to save two framerules over this TAS.
In 1-2, everything up until the end is solid. However, instead of taking the normal way up, doing a clip through the end pipe or a wall can get you to the warp zone faster.
4-1 is pretty good, but a flagpole glitch at the end can save a framerule (21 frames.)
4-2 is very slow, even when taking the vine. In addition, there are various methods of doing a wrong warp to save a significant amount of time.
8-1 and 8-2 could be optimized a little more, and you should slow down in 8-3 to avoid fireworks.
8-4 is overall pretty slow. Particularly the third room, where you could just go past a certain pipe and turn around, then go down the pipe you originally passed to get to the water section.
Hope this helps some!