The Steam page for Extraneum has been approved and is now live! The actual release, which will introduce episode 1, is planned for June 15th, but in the meantime you can already view the store page and wishlist the game.

https://store.steampowered.com/app/1999140/Extraneum/

For those who bought the game prior to June 15th, you'll be able to request a Steam key free of charge. Subsequent sales won't be eligible for a free Steam key, however.