That cinema looks great @crocobaura and it's nice to see the Sims sitting there (not entirely sure if they're actually watching anything).
I tested a few ideas. First we have the fancy staircase - kind of ruined by the actual stairs being rather limited in their possibilities.
https://64.media.tumblr.com/b7f3cd3881764b17fea7acf61e86130c/b9013c5ce083d4d6-a0/s2048x3072/112892a9791065c8be36fde499e2177c74f9f3c8.jpg
Since you can't place platforms next to foundations, I covered it up with topiaries - didn't have to use MOO for it to look okay.
https://64.media.tumblr.com/f35ffedd0f7c5463d5bf78737dc9feb9/b9013c5ce083d4d6-1a/s2048x3072/741d9b85b5be27609fd8ea91b6e2887b7e28a1a0.jpg
Though this probably looks more elegant if you put shorter, broader pieces of stairs in between the platforms. But you can have the fancy rounded stairs (a bit of a hassle though, and you need to use a broad trim to cover up the non rounded inner curve).
My next experiment was far more interesting - hot tubs (with my version of the Caliente sisters (who else?) - modeled after their TS2 versions). I know someone posted a slightly sunken bath tub, so I thought, maybe we'll be able to finally have sunken hot tubs. We can - kind of.
You can place a higher platform around a hot tub that's on ground level, but you need MOO to do this. And you need to leave one side open for Sims to get in.
https://64.media.tumblr.com/bf8086966ab73850a2c1dca37b1a29d8/8c5a62262118ebe4-d1/s2048x3072/4bb3aa3e4c10f52d10c0dede061aff03ce5d9e4e.jpg
You can however, sink the hot tub and place it without MOO (makes no sense at all, but that's build mode for you). However, Sims can only get in if the tub is sunken no more than a single step. So I made a fancy little stairway (that you can build in many far more interesting ways) - and it works!
https://64.media.tumblr.com/09d1ef1c6cac4298bd1517c0c9cd03cc/8c5a62262118ebe4-a8/s2048x3072/f2f26da6909af870ee3fd8506f77eda5014e7ec3.jpg
You can probably do something similar if you go for the first option and build a platform around the hot tub instead of sinking it.
Curious thing is, Sims can get out on the side of the platform - they'll be stuck in the platform for a split second then pop up to the right level.
https://64.media.tumblr.com/9cb661bec60b1fcb890fc621584b1234/8c5a62262118ebe4-0b/s2048x3072/de01a37496b9ced1d5824640c495d57822685a99.jpg
https://64.media.tumblr.com/90061415d14b29b56bc6f51a568b2c28/8c5a62262118ebe4-93/s2048x3072/5f174c0cbe0fd6149e74a4299bc215bdc56efaf5.jpg