PlayTogether Studio have announced their multiplayer escape room puzzle game, Mad Experiments: Escape Room, is going to releasing in April and you can try an early build now.
You can try it solo and online with up to 6 people total, however there's no matchmaking you need the name of a hosted room so gather a few friends if you wish to try the co-op. The developer said that "The rooms are filled with riddles, clues, and mysteries to uncover. Almost every items can be interacted with and examined in details, explore!".
As long as it's somewhat successful, they plan to continue adding new content to it including "new rooms, puzzles, challenges and stories".
PlayTogether Studio is a tiny solo indie outfit formed by Clem, a developer who moved from France to Canada around 7 years ago and worked through both indie and AAA teams before forming their own to focus on pushing the boundaries "of what games should be: a form of art that brings us together and makes us better".
You can wishlist/follow Mad Experiments: Escape Room and try the demo from Steam.