1. The monster felt less like a monster and more like large wildlife. This may be what you were going for, but in the view of Iron Lung I think that the monster needs to feel a little more unsettling. Show the player remnants of the last guy who came down here, or low res pictures of an alien figure. Sound design would also do wonders here.
2. Moving the ship was relatively clear, but other parts of the ship felt slightly disorienting. I wanted to use the paper map but the radar is so zoomed in it's difficult to make out any features. Repairs weren't frustrating but just felt a like it didn't have much impact (even if it let me move again)
3. I think repairs could invoke more of your goal if you had to hold down on each element for a certain amount of time, maybe adding a quick time event if you'd like the gameplay to be a little slower. The repair panel could also feel a little more connected if it was underneath the center console since that's where the buttons went out.
4. I wouldn't say it was too hard or too easy, but not balanced either. I just felt a little at the mercy of randomness, meaning sometimes I would hardly see the monster and others it would be right on top of me. Maybe a one shot kill from the monster is too punishing since the player can't know where they are, what if it shook the hull violently and gave the player a scare, then reset itself on the map. That could increase tension a lot!
5. Ship speed is about how I would've expected it to be. It fits well with the tightness of the local walls, but turning around from a dead end that I spent awhile going through took a little longer than comfortable.
6. I'm not really sure if I made it to all the areas, my position felt like more of a suggestion than a location.
7. Oxygen never killed me since I never really had a need to open the window. The monster one shot me way before I was below 60%.
8. I think the sound design and other polish features mentioned would go a very long way. Iron Lung is a super simple game and doesn't ask the player to do much of anything, but it gives such a thick atmosphere and some tantalizing lore to the player which hooks them, so I don't think anything has to be added, just refined.