Really cool mechanic! Swinging around with the grappling hook is awesome, and using it as an attack is also pretty cool. And the Metroid vibes are really nice too.
The only problems i've found is that sometimes the hook sticks to the wall behind me if I am too close to it, which gave me a problem when escaping from the "moving wall" boss, which ended up killing me, and when the game reloaded to the checkpoint it froze, so I had to restart the game but it seems that my progress was not saved, this might have ben a bug which is a shame because I could not finish the game because of it.
Also the writing in the notes is really interesting, seeing the different unique stories from people in the base made me intrigued, but I also felt that some of them where too long to be read at once, this made reading them too slow and affecting the pacing a little bit, which was a little unmotivating (is this a word?lol), so perhaps an ideia is dividing the paragraphs into two or three different notes to make reading them not only quicker, but also create a "puzzle" type of story, where you discover little by little the pieces of the narrative, just an idea.
Also, the map system was very well done and super useful.
With everything said, this is really awesome, if a save system was implemented and with a little bit more polish this would be perfect, so congrats!