17 frames saved in stage 3, segment 2. the movie desyncs after the miniboss due to animation frame rule. Also note that the rest of the movie remained unchanged.
In order to achieve this, I simply used the bubble barrier again, just before segment 1 ends. This saved 10 frames.
Also, I discovered a new glitch. At 44842, you may notice that Zook does dash on ground right after the Flame Dash is ended, without having to mash the R button, but just keeping it. The game is actually continuing the ground dash started before the Flame Dash. Thanks to a different Y value, Zook managed to stay on ground after the flame dash ended, so he didn't need to jump and the ground dash didn't get broken. This saved 6 more frames.
Lastly, 1 frame was saved, probably for the different Y value, near the save platform.