Thanks for the feedback. I don't have a Linux machine to test on unfortunately... I did test on Firefox, Chrome, and Edge (mac and windows) and it runs at 60fps just fine. And it does replicate the original arcade game play almost to the pixel. (I actually compared frame by frame with a MAME emulator while writing it...).
This was written from scratch in javascript as an academic exercise, so I didn't have the convenience of any canned shaders (for scanlines) like Unity provides, and I did not have a fullscreen itch.io mode in mind either. Putting it on here was an afterthought. Those things might be an idea for if I ever do a re-write, I guess.