https://cant-get-enough-games.itch.io/the-old-gentleman
mechanics are pretty simple but good atmosphere. short and sweet so it doesn't wear out its welcome. you are on a sub stranded at the bottom of the ocean. your diver buddy is with you outside the sub and he can collect parts. but there's this...thing out there. send pings and morse code to your diver and he can collect parts, tell the diver to avoid the...whatever it is, and fix the sub. turns out you learn morse code pretty fast when you see a monster slowly heading towards your only hope of survival. does save checkpoints so you don't feel angry to have to waste time because you did 3 dots instead of two by accident.