It was suspenseful, and at first I wondered how they would make an entire movie off of just this. But the hallucinations didn't make all that much sense. Yes, you can get hallucinations under extreme stress like that, and they can be EXTREMELY crazy, all of these movies are now just a bit predictable
I wouldn't watch it a second time but it was good (ish) the first time!
Random fun fact: there IS a difference between the fear of heights (Acrophobia) and fear of falling (Basophobia) Acrophobia might come from a traumatic experience of falling and Basophobia is just... the fear of falling (little or big falls, I have this fear actually)