I used FCEU 0.98.12 because in this version of ROM will have 300 seconds in 1-1 (and will be a little faster).
I use 2 warp zones.
In 8-4 and many world that have piranha plants, I made a close approach collision abuse. (Lip jumps and jumping through hammers)
I ran the game in 05:09 without taking hit and death.
I tried to make continuous backword jump and lip jump (I think i missed 6 times) as more as possible and make light jumps when there a staircase but I forgot at 4-1 :( and i made 2 braking down the pipe, but still aiming for best time.
The one thing hard is when the title screen show up, in the first frame, look at WORLD text in status bar, it was 1-1, and the next frame, it will be 0-1! that makes me 2 rerecord.
I use Copy of Super Mario Bros (JU) OK.nes because I'll hack the Super Mario Bros (JU) OK.nes and now that rom is no longer usable and OK means that ROM works (I have many rom, some not work!)