We of course have horizontal hatches, and the moonpool acts like a floor hatch, but having a moonpool on the roof of a room would be so cool. Vertical windows should also be a thing, and I’d love to see round rooms back with a round ceiling. Maybe an option where if you’ve selected the room then aim at the corner of an existing room, you would make it round, just how you can change the shape of windows.
Skylights = Yes please, Flat and Dome variants please.
Almost like Subnautica and Below Zero, that would be very nice, also i would personally want when the hatch has stairs/ladder for building on land!