I've been redoing my submitted run from scratch. I've just finished world 1, and have saved 20 frames over my last submitted run so far:
*4 frames saved on 1-1 by picking up Wicky without jumping, and optimizing the section around frame 820.
*4 frames saved on 1-2 by not slowing down at the beginning of the level.
*12 frames saved on 1-3 by faster boss fight.
Here's the .fcm. Please post any ideas/comments you might have!
I have analyzed in detail how the herb moves and where I should kill the boss in order for the herb to appear at a convenient place. I can post details if anyone's interested.
I have also found a way to zip through flag poles, but this resets your speed to 0, so I'm not sure it will save time anywhere.
EDIT: Just finished 2-1, and boy did I save time here! I used narimasa's strategy at the beginning of the level, and managed to get up the height around frame 6450 much faster. All in all, I saved 71 frames on this level alone! I'm quite amazed, actually.
Here's the .fcm.
EDIT2: I don't know if anyone reads this, but anyhow: I've just started world 4 now, so I'm about half-way through the run. I'm saving a lot more time than I thought - I'm already 9.4 seconds ahead of my submitted run. Both 3-1 and 3-2 use wall zipping.
World 5 will include zipping through flag poles, there are two places in this world where this will be included. I think his new run will look great!
I've switched emulator to FCEUX now, so from now on all WIPs will be in .fm2 format. I hope no one minds.
Here's the new WIP.