I'm not sure about the "omg best episode ever" talk, I tried hard not to be caught up in that expectation. But still, wow...
It was beautifully done and acted. I nearly welled up, possibly because the characters of both reminded me of my own relationship a little bit, and then watching ourselves and our bodies change and grow old. It was particularly poignant because they had their perfect little world away from everything, protected by Bill's traps/paranoia. And that Bill found some happiness (and a bit of COCK, obviously) was a lovely ending for him. The twist of Frank being ill years later was heartbreaking.
In the game, none of this happened. Bill was an (understandably) crazy man who lived in his booby-trapped town. You don't see Frank - any relationship is only alluded to by finding letters, and the suggestion was (I think, it's been ages since I played) they fell out as Frank didn't want to stay there. Bill never knew what happened to him, and you then later (as Joel and Ellie) find Frank's body hung in a garage with a suicide note
The TV version did it MUCH better given there's enough misery to contend with. It was only a small part of the game so changing it worked without affecting the story. Amazing work all round!