There is no way you completed every single main quest/side quest and cleared every dungeon, fort and cave in 80 hours. I just do not think its possible.
But it is. I posted my stats earlier in the thread. Unless there are
way more locations than 344, I've been just about everywhere, and I've cleared over half of them. A lot of the locations simply can't be cleared. Now, I
do play on novice and I recognize that makes a big difference, but I play these games to experience the world - not spending hours fighting a dragon hoping to win. I've also played with another character before, so this isn't my first rodeo. I knew pretty much where every quest was located and what was in every dungeon, so that drastically reduced my hours as well.
I'm
not complaining.
Skyrim lasted me far longer than any game. I beat Dragon Age II, doing everything, in about 30 hours. I got 100 hours out of my first
Skyrim character and 80 out of my second. That's damn good. However, it's entirely possible to do everything in the game and fall well short of the 300 hour mark. I don't like people calling "bs" on people who say as much because it's entirely possible.