Alright, I'm back!
The deadlines have been met and I'm now breathing easier, so DROD architecture is back on the menu
@Fogel: Both of your approaches for 1S are way away from my intentions. I won't say they are impossible, but they sure look so

Earlier on, in one of your first comments you said "
but I'm guessing the idea is not to drop the highlighted trapdoors?"
, which is in fact false and I should have flagged it for you immediately.
The idea there was to have
those trapdoors be the ones your first pass drops.
So I ask, should I make the highlight a different colour to signal this? Or replace the trapdoors with pit and add some kind of a one-time-tunnel passage to the other side?
What do you think would help in this regard?
It might take me a while to regain my footing here with where the needed upgrades are, bear with me. (But hopefully by the time I get a useful tip for this, I'd have managed to progress.)