The damage animation can be cancelled by firing while getting hit. Should save significant amounts of time: This incredibly short section saves about 70-80 frames by itself just from 3 cancels.
#70649600500999896 -
ewj2imp.bk2
In 00:19.45 (1169 frames), 4847 rerecords
4 comments,
285 downloads
#69964139650210538 - EarthWorm Jim 2 (Shin-Shin)
EarthWorm Jim 2 Unl p1.bk2
In 09:43.59 (35073 frames), 4078 rerecords
238 downloads
Improvement (20 frames) at Round 5-2 (Found by Memory)
#68962035464123494 - NES Earthworm Jim 2 Small Improvement 2
Earthworm Jim 2 NES Improvement 2.bk2
In 09:43.59 (35073 frames), 4030 rerecords
293 downloads
20 frames saved at about frame 19000, probably also applies to other segments, also probably not extremely optimized.
#68962010294720545 - NES Earthworm Jim 2 Small Improvement 1
Earthworm Jim 2 NES Improvement 1.bk2
In 09:43.89 (35091 frames), 3805 rerecords
306 downloads
2 frames saved on the level that starts at frame 5727, probably more possible.