One additional thing I noted down during a replay: when you're next to / near a switch of any kind, I think the game could visually highlight the relevant object(s) (or at least their icons) that the switch affects. As it is, it's generally faster to just toggle the switch and see what happens than it is to stop and visually scan over the level to see where the relevant icons are. If those icons were automatically highlighted in this situation, it would basically get rid of that time-consuming visual scanning as you could immediately home in on the highlighted bits to see what's going to be affected.