E. laser is used for the quick destruction of the bosses. Bonus stages were skipped for boringness and length.

Stage 2 boss was the most difficult part to do fast since it is so hard to hit him without options. Too late I noticed that I missed couple shots in that fight, so I didn't bother doing the whole run again. After all, even Morimoto missed many shots in his Gradius video ;>

Choosing Arcade-mode in options takes a while because you have to press A-button rapidly for a short moment

This game also has some really good "engrish" in the epilogue when you beat the arcade-mode :>

Bisqwit: Selecting the "Arcade" mode took indeed time - I was going to reject this movie because of it, but since you explained it, I had to try whether it really can't be done faster.
My attempt is here: https://files.tasvideos.org/common/SubmissionFiles/55S/gradius3-arcade-menuonly.smv
I managed to do it faster than you, but only marginally. I did it frame by frame, as usual.
I hope you fix it in the next version :)
This movie looks ok. I'll process it.