While playing the game, did you...
... scream like a little girl whenever a monster spawned close by?
Yes! I was terrified every time a monster appeared, often having to pause the game.
... boast to others that the game wasn't that scary only to shit your pants shortly thereafter?
No, I told all my mates how amazing it was and how it was the scariest game you will ever play.
... at any point have to quit the game to give your heart time to slow down and/or your hands to stop shaking?
Yes, as I said earlier I had to pause the gamer sometimes just to calm myself down and often when I encountered a particular scary moment I would quit the game and come back to it a few days later at least.
... die more than once - because you were killed by the same monster?
The only time this happened was with the water monster. My fear of water was created then.
... regret that you turned the handle and allowed a certain someone to talk to you?
No, I'm glad I got to have someone "normal" speaking to me, well at least he wasn't trying to scoop out my eyeballs with a spoon.
... feel too frightened to open a door, because you thought a monster might be on the other side?
Yes! I remember in the study when I was very new to the game I wouldn't leave this room as I was certain there was a monster outside of it. I refused to play the game for weeks but in the end there was nothing there -_-
... feel too frightened to pick up what you had come for, because you knew a monster might spawn?
No, because I got too excited when I realised I had found what I was looking for and any thought of monsters evaded my mind. "You have to know how foolish I was".
... pass out from low sanity while waiting for a monster to disappear?
Definitely, in a believe the storage area (near the weird baby snake statue vomiting water). When the first scripted monster which attacked you there came out I was terrified even after it gone.
... pass out from low sanity while hiding from a monster that wasn’t even there?
No, I just hid in an isolated area for days.
... attempt to flee from a monster only to run right smack into it?
Most certainly yes! This happened to me more in custom stories than in the main story. I remember one time when I was playing the "Find Stephano" pewdiepie map a brute appeared right behind me, me being scared and acting very stupidly I thought it was infront of me and decided to run back the way I came. Turned out a mean looking sword wielding zombie (a brute) was waiting for me at the door.
... jump off the window ledge in the study, just to see what would happen?
I did indeed. I thought I could escape the castle that way. At the time I had no intention of killing Alexander I just wanted to get out of there!
... jump off the window ledge in the study and then laugh like a maniac when you died from the fall?
Afraid not. Maybe I'll try that in the near future.
... spend a few minutes giggling insanely as you threw various objects into the vat of acid?
Of course! Who hasn't? I spent ages seeing what I could destroy by putting it in the acid tub
... pick a hiding spot and realize too late that it wasn’t a very good hiding spot?
I can't think of any specific times in Amnesia but I do remember this happening in Penumbra Black Plague. With the first monster encounter I hid behind the desk in the room you're in. It turns out it was better to hide in the corner of the room out in the open as I survived doing this while died hiding behind the desk. (I was playing on hard difficulty)
... play through the game multiple times only to find out to your unpleasant surprise that things were slightly different that time around?
No, I haven't played through the main story since I completed it!
... go back to an earlier save and play an area over again because it was so damn much fun?
I was just too scared to go back to an earlier save.
... frantically try to stop the elevator when things started to go south?
Nope, I was still traumatised from all the monsters I encountered when trying to fix the elevator.
... curse the Shadow six ways from Sunday when it showd up and ruined the sanctity of the Back Hall? (Bonus points if you did so in more than one language. XD)
No, I was just super scared, as always
... curse the Shadow six ways from Sunday whenever it showed up and made your sanity go from "Slight headache" to "omgwtf I'm dragging my face along the floor!"?
I didn't curse in six ways, I just usually stated "Oh, balls" when such an event happened.