long loading times. Today's PC patch for Deus Ex: Human Revolution should cut down the time. According to the patch notes on Steam, some machines have seen load times decreased by over 50%.
On top of the load times, a start-up crash affecting certain AMD/ATI hardware configurations has been addressed. Mouse sensitivity has also been tweaked, which should hopefully alleviate that problem you had where you would keep running up to dudes and punching them in the face, over and over again.
Oh, wait, that's how you're playing the game? Well, carry on then.