I love Thief: The Dark Project so much I push for its inclusion in the PC Gamer Top 100 every year (and sometimes I get my way). Seems like Thomas Porta loves Thief too, as demonstrated by the footage of his upcoming stealth game Serpens: Eternal Thievery. As well as a gameplay trailer there's a video from the current alpha (embedded above), which shows the first 10 minutes of torch-snuffing abbey exploration and has convinced me to add Serpens to my wishlist.
The level has a hand-drawn map, opens with a religious quote, and has fireplaces to crawl through. There's a light gem in the interface, NPCs hum to let you know where they are, and conveniently placed boxes can be climbed on. Torches can be put out, guard's bodies picked up, and doors are highlighted when you're close enough to open them. (I dig that doors can be opened halfway to peek through by holding down the key as well.)
Basically, it's playing all the hits. So many subsequent stealth games left out vital parts of Thief, whether it was leaning or the ability to move bodies, that I'm happy to see them copied here. Put some stacked boxes beneath an open window and I'll probably play your game. Serpens looks like it's more than just a clone, however.
For starters, it's got a much more medieval vibe. The Thief trilogy was set in a fantasy world going through an industrial revolution, and felt like a steampunk-ish take on noir. Everything about Serpens seems to suggest a pseudo-English Middle Ages, from the dialogue to the interface, with menus that look pages from a hand-lettered manuscript and a health bar and light gem right out of marginalia.
The labeled leads that pop up when you overhear gossip seem like a bit of a Hitman touch, and there's an element of time manipulation that suggests Outer Wilds. It turns out Serpens is a god who has blessed you with an amulet that lets you loop time, which will come in handy since the clock moves on while you play, as denoted by the monastery's bells. How looping will differ from a simple quicksave system remains to be seen, but I'm interested in finding out.