It's pretty interesting. Some plotlines and outcomes I expected, some definitely not (like attacking a guard with a sword in hopes of cleansing the humankind with the virus).
I don't think the intro is necessary. There's no denying that it's cool, and judging by my own experience, all those camera angles must have been a pain to animate… but it doesn't affect the story or gameplay in any way.
Of course, unless there's some ultimate ending or secret which takes place in the hospital and happens to *you* after you earn all the endings (e.g. you uncover tidbits of information about your situation and the hospital through the life simulator, and then there's a final cutscene). I only reached a couple of the endings, so I wouldn't know; but it'd be cool.
I also wish you could skip the typewriter animation (e.g. by pressing any key), because you go over the same initial passages over and over again and don't want to wait for them to load. I feel like I'd have to draw a decision tree to earn all endings, but it's probably fine, since things like checkpoints and going back would ruin the concept that you're controlling a new person, a new life after every ending.
So in summary, it's a text adventure in a really nice package, but it's intriguing and there's a lot of variety.