Ok, so I am at what I assume is literally the very end of the game. I have Ellie and escaped into the elevator, but as soon as the door opens, the screen goes black and never comes back. I tried replaying the section, didn't help. My question is, is this a known issue with a work around? Is it something specific to me? Or, is all the interactivity of the game over and could I just youtube the rest?

There is one short control section after this where you walk up a hill, but yeah, you're pretty much finished now. That's a shitty place to run into this kind of problem though.

The only thing you are missing is a cutscene and a short walk in the woods followed by the another cutscene and the credits, so if you can't fix it, going to YouTube would be a fine at that point.