I’m just picturing big chambers like Super Metroid, and the characters moving around testing things to see what happens, then putting it together. (Maybe a zoom out button, or the map screen being relatively detailed.) So it could be very similar to the original, just “more”. You’d just need a few sets of puzzles in every chamber, for when they backtrack and revisit areas. Mind you I’m not saying it’s easy to “just” design good levels and puzzles, especially in such a large scale, just that it’s easy for me to imagine it being fun.