An awesome and satisfying escape room game. The entire thing was cool and challenging and made me feel clever. I think my favorite puzzle was the sigil game.
The atmosphere is amazing as well, with the excepetion of the HUD on the submarine. 

Also, putting beta art over the credits was fun.

I have one comment that isn't strictly positive, but it isn't actually about the game-it's about the description. Knowing how obtuse some games in this genre get, I don't know if I'd give this a 4/5 on difficulty.