Creator here: Yes, that's bugging me too. I think the default "monospace" font on Android is def not monospace. I'm going to look into embedding a font instead.
On Chrome (Windows) the box frames at the bottom are no right-aligned either.
Have you thought about using <canvas> and just writing OEM DOS style characters where they need to be like some sort of obscene franken-video-buffer?
It works fine on my iPhone, perhaps it’s not setting a correct proportional font on android?
I think you're right. I tried this on Firefox for Android. Looks great on Firefox for OSX, though!
Firefox destop site switch improves the rendering, but still..