The ending was pretty simple... Yet, there was too much that still needed to be told. They had to cramp every second they could into this episode, (They even took out the begining theme song). I knew that somehow when it came down to the countdown, we would truly never actually see them IN the 80's. The countdown ends with Eric's basement. A truly deserving place for the last scene.
Where was Laurie (The sister). In the first few seasons she was always gone, then in the 6th season they got a new actor.
Since That 70's show is a Comedy show there was always jokes and punch lines in between serious moments. But when they do have serious moments they cause a great impact on us because they are not as common as the punch lines.
The show credits end with the whole gang singing : "Hello It's Me" (1972) Todd Rundgren. (But they tried to sing it) That credit is rather ironic because it actually comes from the Pilot: That 70's Pilot.