Wait - what? Spoiler I got caught by the hidden zapper, of course . But then when i tried again, stepping carefully to explore... it didn't zap! Did i get through by accident?
I must confess.. Spoiler I can't get past the zapper consistently - I wish that I could! I can see that it seems to rely on B skipping a step or two on his way down the stairs, but I can only achieve this about 1 in 10 times. But thankfully.. Spoiler I found a way to avoid the treacherous stairs, and this i can repeat reliably: as B jumps the gap, tap on the lower layer where his foot stumbles. He will abort his struggle over the gap and descend to the lower grass layer for the win. Extra stars for extra solutions. And for the artistic architecture and the time you took to create it. Thanks @meko!