There's a small forced tutorial the first time you start the game, did you try opening the pause menu with tab? The door won't open until you do that. Definitely not the clearest though
Hmm, that's work. But feel really strange. Especially by no other info in menu. (At first play I open menu, but only at end of trying to open the door, and sawed no new info just exit game)
And honestly two keys one from it obvious won't see as tutorial.
Any way thank you! I haven't played this game yet, but like your other games, and think it's be cool too!