No, no, that's not it, Diman! You still play like you don't have enough time and tools for your assistance.
I can understand losing some frames during the level, but why did you wastefully jump at the end of this level? Normal walking from this point ends level 16 frames earlier. You could try this as one of several possible ways to reach point B (all sprites are gone - frame 1365 in your FCM).
To achieve fastest completion you should try many different ways (and maybe not-so-different - even 1 frame difference sequence should be tested), comparing them to eachother EVERY SECOND (or every 100 frames, or some other checkpoint - you name it). If you just walkthrough a level several times and then compare those versions, you won't allocate strong and weak points of each way. You should analyse it precisely.
Here I recorded good example of this level strategy. It's good because it contains a couple of interesting moments. Look near frame 1165 and then near 280. Notice that sometimes it's better to postpone rolling (for letting screen scroll) and that bumping a barrel (or whatever it is) not only moves you fast (still rolling is faster) but also scrolls screen faster than usual (that's what important here!)
Frankly, I had plans on making this run improvement myself, but I got bored at Channel 5, so you'd better follow your signature! First, try to beat this level example (even 1284 would be good) - just be creative and eventually you'll find a way.
Well, if nothing can be done here, you may insert my sequence using hexeditor. This game is hexedit-friendly (you can easily cut and paste sequences whithout fearing that it would affect next levels randomness), so maybe good tactic is to record each level separately, then choose best versions and assemble them into one (I've done this for CS-Jetman movie, and LettleMermaid is completely unfriendly to such method - it changes everything if any frame were modofied).
Uh, and what about taking damage, have you decided? As for me, no-damage run is more valuable, taking damage saves only few frames in several places, it's nothing, you can run the game in less than 20 minutes without it.
Well, good luck!