Emulator used: FCEU 0.98.15 rerecording
Needs L+R enabled
Aims for fastest time
Takes damage to save time
Abuses programming errors in the game (clipping, L+R)
Manipulates luck
This is my final version of this run. I don't think I can get any more out of it. It's 492 frames (8.2 seconds) faster than the published version. It's actually my fourth version of the run all told. I submitted the first at 11:14, had a second at 11:10 that changed routes in a couple of screens and optimized a bit, then a third at 11:07 after I discovered that L+R works and gives you some interesting options in controlling your jumps. Neither the second nor third were submitted. I made some changes to the third one and ended up with this.
L+R puts you at full speed moving right, even in midair when you're faced the wrong way. This allows for some nice tricks. See the second to last screen of 4-3, and last screen of 5-2. It also allows me to climb up walls with a 2-frame cycle instead of a 4-frame one, when on the left side of the wall, at least. It's not actually faster it does give me more accurate jumping-off points. Also, you may not be able to tell, but L+R is critical to my new strategy on the level 3 boss. Without it the jump where I use the sword would pull me badly out of position. With that trick, that fight sparkles.
Surprisingly, though, most of my time saved comes from much more accurate transitions to and from walls and ladders. It's probably at least half the total time difference. Some of this is aided by L+R, but not all of it. Between my first and second run, for instance, before I used L+R at all, I gained at least 6 frames on every screen of 5-3 just from better ladder usage.
In the latest version I also had very friendly luck and was able to gain about a second by taking damage to boost myself to ladders in two different places. This just happened to work out perfectly, without me even having to manipulate it, and it looks very nice.
Anyway, enjoy.