There are games I never want to see again. Red Dead Redemption is one of those games, and L.A. Noire is another. The explanation is simple. They are great game for 15-20 hours, but in order to finish them you need to spend 30-40 hours. And those last hours, you just want to kill yourself. It is so insanely boring, and you play just to get rid of it.
Designing a game as such, great gameplay that lasts 15-20 hours, but a game that drags out for twice that time, will make sure that you never revisit it again.
Now, Skyrim is the opposite of that. It has a main story that goes on for about 10 hours, that is not very interesting. What is great about Skyrim is all those side missions that are optional. There are just so much to do in this immense world.
It is a beautiful game, with vast stretches of landscape that is just a beauty to behold. Someone said that you don't have to play Skyrim to appreciate it. Just start it up and walk around - experience it.
And that is the greatest strength about this game. It is the world that is interesting and exploring. You can't really explore it all, so you play until you're bored. If you want to finish the game, you have just a small amount of questing to do.
This is a game that I think about now and then, that I would like to pick up and continue my character. Yes, I have completed the game, but there's just so much more to see and do. I believe that I'm not quite finished yet.