There's finally some more info about the game on Bethesda's website https://bethesda.net/en/game/deathloop
The gist of it seems to be:
The player controls Colt, the guy trying to end the deathloop by assassinating 8 targets across the island in one day.
The player's abilities are customizable and stealth, guns, and powers seem to be the primary skills you can focus on.
It's a PS5/PC exclusive.
Juliana is trying to stop Colt from completing his mission. She can be controlled by AI or by another human, who can "sneak into another player's campaign", although this is totally optional.
During each loop you're trying to uncover hints to help take out your 8 targets.
The setting is 60's retro-futurism.
This sounds pretty awesome, I can't lie. Then again Arkane could probably release a version of Monopoly that doesn't suck.