I came across this article about Pilotwings Resort, which was what I was going to blog about, but he said it better (well... as good as) I would have, so I'll just link to that and go from there.
Now I've only put 10 hours into Pilotwings and experienced about 98% of it (only four more missions to perfect... free flight is already finished), so that'll probably put me at about 10:30-11:00 total, but that's still four or five times longer than many people are citing for the length of the game.
There's more to experience in most games than just the critical path. I called this "vertical gaming" in a previous blog, but I'll make it even simpler now and just call it mastering a game. It feels good. That's pretty much all there is to it.
I know that I've almost mastered Pilotwings at this point because the early missions are extremely easy now and I feel totally comfortable with the controls.
It was the same with Super Meat Boy. I did everything possible in that game, which took a lot of perseverance and dedication, and the result was extremely rewarding. And it's not just like one big rush of accomplishment when you see that final level beaten.... Every little victory along the way feels just as great.
How often do you really sit down with a game you enjoy and try to squeeze everything possible about of it? I still have Donkey Kong Country Returns to finish (Mirror Mode only... already did everything else), Epic Mickey (it'd be great to find all the collectibles and try using thinner instead of paint more often), Trauma Team (a few more missions to S rank), Goldeneye (still a few more difficulties to go through), Mario vs DK: Miniland Mayhem (almost through Plus Mode), Super Scribblenauts (working on gold crowns) and probably more that I may or may not get to.
It's literally impossible to get to everything in every game, but do you find yourself even trying? For some reason, it really bugs me to see that someone has just worked through a game to get to the credits and move on to the next one, even when they enjoyed the game. If you really liked it, then why wouldn't you want to spend more time with it?