DaSmileKat | [TAS] NES Super Mario Bros. "AEPLLG" by in 4:40.422 by DaSmileKat @dasmilekat5231 | Uploaded September 2020 | Updated October 2024, 2 hours ago.
This TAS uses the game genie code AEPLLG, which allows jumping in midair. The RTA timing for this TAS is 4:37.160.

Commentary:
1-1: AEPLLG speeds up the underground section because you can land on the platform and gain running speed earlier. It also allows a trick known as FFPG, which saves well over 2 seconds on each flagpole. It involves clipping into the flagpole base and hitting the flagpole from inside the block, but at a lower position than normal FPG because of the usage of AEPLLG.
1-2: AEPLLG allows clipping through blocks from below by repeatedly jumping, since the upwards speed you get from jumping is faster than the wall ejection speed. Also, you can jump below the lowest layer of blocks. This is used to speed up the warp zone by going under the ground then through the pipe, which saves a framerule over clipping into the wall to the left of the warp zone. Turning around before the final jump into the pipe is slower by 1 frame because you land 1 frame later.
4-1: Nothing special here, just some midair jumping and FFPG at the end.
4-2: With AEPLLG, it is possible to clip into the first wall as shown in this TAS, which is the fastest place that you can clip in to gain x position to trigger the wrong warp. Using the vine to teleport to the right is potentially faster, but I wasn't able to get it to work. Clipping through the bottom of blocks is again used in the warp zone, saving a framerule over the normal turnaround method.
8-1: Again nothing special.
8-2: The time counter on the top right pauses when you're very high up. This is used to manipulate the time counter, so that fireworks are avoided.
8-3: Again manipulating the time counter to avoid fireworks.
8-4: If you die, the screen stop scrolling. However, with AEPLLG, you can jump up after the game thinks you're dead from falling into a hole. This means you can go all the way to the far right side of the screen by simply moving. For some reason, the pipe, as shown in the TAS, takes you to the next room when entering it from the far right side of the screen, saving a lot of time. Surprisingly, waiting until landing on the ground to use left+right to slow down quickly is just as fast as the turnaround in HappyLee's normal warps TAS, despite scrolling the screen an extra pixel. I don't think this turnaround is perfect, but I wasn't able to find any faster method.

Movie file: gofile.io/d/rQpACV
Emulator used: FCEUX 2.2.3
Framecount: 16853
Rerecord count: 7241