Thanks!
Funnily, I had forgotten that there already was a published movie, so I did not watch it while recording this, so I missed a nice trick in the final level. It saves about 75 frames to jump on
both ghosts in the spike room. It will cause damage, so a health refill must be taken from the Martian, but getting it will waste much less than 75 frames.
In my run, I wait 1 frame before starting the game. This avoids 2 lag frames after the Road Runner level, thus saving 1 frame. I wonder if there is a way to get rid of those lag frames without waiting in the beginning.
Edit:
Saved 74 frames by taking damage in spike room, lost 18 frames getting health back, saved 1 frame in final boss, total 57 frames improved:
http://dehacked.2y.net/microstorage.php/info/896743388/LooneyTunes-14038.vbm
Thanks to Sonikkustar for recording some parts to improve entertainment. In case somebody wants to try improving the last boss or some other part, I'll leave this be for a week before submitting.