I beat all the levels, but I never figured out what the difference between "A" and "B" connections were. I didn't seem like I needed to ever use a "B" connection and when I did, the code just seemed to ignore it and only run "A"
Also, I suspect that the "do nothing" command just causes him to wait a tick, but I don't know for certain because I never found myself in a situation where I needed it.
I really liked this game. More than any other cove-like so far, it felt like each level had an infinite number of solutions. Mainly because you could make your code as efficient or janky as you wanted. So I wonder if anyone else found uses for "B" connections or "Do Nothing" commands.