Princess Rescue is a Super Mario Bros. inspired platformer for the Atari 2600. It is a very impressive game for A2600 standards.
I improved 3-3 by 3 frames (one movement step) with a better enemy manipulation. No other improvements were found (I checked the other trampoline level 4-3 a few times but couldn't find anything.)
The same improvement would likely also work for the deathless run.
The run is visually virtually identical to the original, so no need for a temp encode. Occasionally I go through runs as QC for changes I make to various BizHawk cores. A2600 underwent a lot of changes recently so I looked at this run and Halo2600 as a test. That section in 3-3 just stuck out at me so I thought I'd give a try at getting a better manipulation.