Uh-oh, this game is slightly more complicated to optimize than I thought.
The game accepts input (and progresses the animation) in 5-frame intervals, which should make everything very simple. However, the real character position changes even between the animation frames, so it is sometimes possible to exit screens at the "4th frame" instead of the assumed 5th frame. This phenomenon can be used to skip 1 frame in screen transitions. However, in most cases there are enemies and other hazards that rule out the positioning for faster transition.
Hah, take a look at this wicked collision detection! Next frame, the player is dead by the sword:
Aaargh!
Luckily, luring the guards down from the ledges works most of the time. It is usually faster than killing them:
I also found two promising tricks, which both turned out to be useless:
1. Only one guard can be on screen, so if a guard is lured to a room with another guard, it disappears from the game.
2. It is possible to walk through gates by retreating backwards when wielding the sword. Too bad the sword can only be used in the vicinity of guards, so the opportunities for using the trick are very limited.
The new movie is now 2047 frames faster after level 10. Here's a
WIP backup, but I don't recommend watching it, unless you're a really big fan of the game. It looks pretty much identical with the old movie.
Edit: Updated the WIP backup above. It's almost done, yeah!