They look like they're in 360p in every-single-game. I remember when I played final fantasy 13 (ah, bad comparison) a year and a half ago on my pc, using my pc monitor, and they looked fantastic. Whenever I play a game such as Arkham City or Deus Ex they look 10x worse than the actual game.
So, Why Do Cut Scenes in PC Games Look Bad?
I noticed this as well..There a lot of PC games with bad cinematics..Usually the pre-renderred trailers really looked good but the in game cinematics is worst that the actual gameplay.
Best example is Deus Ex Human Revolution - it has a sick trailer that can pass for a movie but the in game cinematics look like the characters are taken from a Lego game.
Another example is Hitman Blood Money, there are others, I just cant remember..