Beautiful
I found a few things while playing.
Some of you will tend to try and be nice to the girl while playing, since you obviously won't realize the meaning immediately. Those who do are perhaps afraid of change, or like happiness far too much, and are afraid that if they lose it, they'll never be happy again. This is probably why you wanted the girl to stay. This is probably why you ended up in the hospital ending, or the ending where she just sorta starting fizzing and fading but doesn't go away.
Those who felt they could relate to the character and feel the need to back away, you're not afraid of change. You're not afraid to start a big change. You explore, you go out and have as much fun as you can because you know that keeping the old habit will just get boring and perhaps dangerous to you.
Or, perhaps I'm wrong with both of this (which I probably am).
For the meaning of this game, it's suicidal tensions (as stated before). You might have been confused when you got the hospital ending (I was at first, too). But now replay the game with this in mind, and see how the girl relates to cutting and suicide, and NOT your girlfriend. Think of the girl as suicide this time. Think of her as whatever you want... Do you still end up with the hospital ending? Or, do you end up with the empty room?
Perhaps you should try and see what you get on the next try, which that in mind.