I was going to do sdw any%, but I've been on the first three levels for a few months with no signs of progressing, so I stop.
mi1: no new info. my wip starts at entering mi2 in the current published run. the current run doesn't enter on the first possible frame :D
mi2: while doing 6/5 and going down a slope, you can get a spot where your speed instead of going 49,49,49,49,49,49,48,47,48,47,49... it goes like 49,49,49,49,49,49,47,48,47,49 or something like that. so you get a 6/4. this can be done twice on the slope right before the the midway gate. my wip of mi2 is faster than all others that i have compared it to.
mi3: if you have troubles getting high enough to open the flower and not fall in the pit, try a 6/10 instead of 6/5 at the pipe right before the last goomba there. it allows you to land higher on the goomba. watch the wip in that spot at frame advance before you tell me what i just said is confusing. maybe your position won't make it necessary.
mi4:
c1: do not take the secret exit!!! this is new.
si:
dw1:
dw2b:
this is a faster method than ism wip posted by Mister. It does not require you to get hurt, so you can keep the flower that you need to complete DP.
DP:
desert secret: get yoshi and the shell. yes, you have to backtrack.
c2b,wsw,dsw,csw i don't recall any improvements. keep yoshi! look at the ism wip for c2b.
ssw: i haven't actually confirmed that you can get yoshi through this level, but i think i recall doing some basic guesswork and convinced myself that not a significant amount of time would be lost.
psw:
this is why you still have yoshi. and why you got a shell. and why you did desert world instead of msw.
bsw:
improvement posted by Mister.
bdsw: if you have less lag,
lava slide might be faster than the method used in the current run. If you have lots of lag like this demo, lava slide is slower.
bowser:
Good luck with fadeout lag. iirc desert route saves something like 7 seconds over going through msw.
here is my wip. it doesn't get very far :P
There's also something like 4 minutes of improvements available in sdw120. maybe i'll make another incoherent post.