This is a TAS of FDS Super Mario Bros. 2, specifically of the letter worlds. You can play the secret letter worlds after getting 8 stars on the title screen, and you can access them by pressing A+Start on the controller at the title screen--as such, getting 8 stars is required before being able to play the movie, which means this TAS starts with an unclean SRAM state. This means a verification movie is required, which can be found here: https://tasvideos.org/UserFiles/Info/638008645247617084 The linked movie gets the required SRAM state this TAS uses to start directly in world A.

Flagpole Glitch (FPG): Used in B-1, B-2, B-3, D-2, and D-3. By clipping into the block at the bottom of a flagpole within a 0.5 pixel window, Luigi can touch the flagpole lower than intended. This activates a normally completely unused bit of code that causes the flag-lowering routine to be skipped, allowing Luigi to finish any levels with a flagpole 21 frames faster than is otherwise possible (in most cases--see the FFPG section for exceptions).

Full Flagpole Glitch (FFPG): Used in A-1 and D-1. By touching the flagpole even lower than is possible with FPG--either by clipping in the ground as seen in this TAS, or by using an enemy bounce like in 8-2 of SMB1--Luigi is too low to snap on top of the flagpole block, causing him to be ejected out to the left instead. This causes the timer countdown to begin earlier than is otherwise possible, which can save a large amount of time.

Wall Clip: Used in every level, in some way. By pressing left within a 1 pixel positioning window, Luigi can be pulled into a block, rather than be pushed out of it as is normal. The amount of airtime Luigi has before landing inside the wall will affect how far he goes inside, as the longer he spends in the air, the farther to the right he will be pulled, which is important due to the fact that the moment Luigi lands, if he isn't fully clipped into the wall, he will be pushed out to the left instead. This effect is only used to get FPG in B-1, B-2, B-3, D-2, and D-3--however in A-1, A-2, B-4, and D-1 it is used to greater effect. In A-1, Luigi jumps barely too low to get on top of the block he clips into, which gives him just enough airtime to fully clip into the corner of the block with precise enough positioning. In A-2, B-4, and D-1, with help from the wind, Luigi doesn't have enough airtime to fully clip into the walls, however with a few extra jumps, is still able to fully clip inside.

Long Firebar Skip: Used in D-4. Due to the fact that firebars always rotate a fixed amount every ~6 frames along their length, the tips of firebars travel more distance than the center. This means that with a long enough firebar, and precise enough positioning and timing, Luigi can be on one side of the firebar, barely not touching it. Then, on the next frame, the firebar rotates, and at the same time, Luigi moves, so that he's on the other side of the firebar without having touched it at all.

B-2: Here, I used a strategy similar to the one Happylee used to improve the B-2 in my Worlds A-D Mario TAS. The movement entering the short maze section allows Luigi to descend faster than in my old submission, which means he can slow down a little less, just enough to save a framerule (21 frames) with 1 frame to spare.

B-4: In this level, I simply improved the movement I used in my old submission, from improving the beginning of the level by falling off the ledge at the beginning, rather than jumping, to improving the end as well with generally tighter execution. Overall, it was just enough to save a new framerule, with 1 frame to spare.

D-4: In D-4, it was discovered shortly after my submissions that it is actually faster to just slow down a little and wait for the podoboo in the last room to fall down, rather than doing a wall clip like I had originally done. This submission uses that to save 11 frames over the D-4 in my old submission, however I do unfortunately have to waste 4 frames in total, in order to both be able to get a good Bowser pattern, and to be able to actually pass Bowser while surviving. This was not an issue before, as in my previous submissions, the wall clip caused Mario and Luigi to be noticeably farther to the right, making Bowser much easier to pass.

ThunderAxe31: Claiming for judging.

ThunderAxe31: Accepting as improvement of the current publication.

fsvgm777: Processing.