Let's be honest there's nothing about cosmic horror in this game :) There's solitude and infinity but no cosmic horror. I find the artstyle of the game a little bland. I really think that Godot is not the best engine to make 3d games. But still you managed to capture the atmosphere of an abandoned spaceship. Drag&Drop inventory is nice but it doesn' make sense that you need to put the item on your hand to use it. I mean the keycards and consumable items. The O2 mechanic is a very good idea. It makes the game more tense and immersive. Oh and you should've make some kind of escape pod or something insid the room where we escape the ship. I couldn't figure out where to go there and got stuck, i later saw in a video how the game can be finished.
The main problem of the game for me is that this is not a dungeon crawler. This is like an atmospheric/survival horror game with a grid based movement system. There are no enemies to fight, it doesn't play like a dungeon crawler. Regardless of my criticisms and nitpickings it's actually good game in it's base with very cool ideas. Nice job and good luck!