I'm not sure about this , but I do know this from what my friends have been playing:
Pirated games are EXACTLY like the original ones-but I researched and I found this.
Certain games are uploaded to pirated sites on the day of release (or that same month),these games have certain drawbacks that prevent you from doing many things.One of my friends pirated Arkham City and I noticed that while my version had cutscenes,his did not (i got mine from Steam),this means that SOMETIMES,there are minor drawbacks.Take for example Assassin's Creed 2,if you get the cracked version,there is almost no way of using it live (online that is) and the same applies for Arkham City (cannot make Windows Live account if cracked).Usually cracked games don't let you go online (they do,but if you do,your game will ask for serial keys etc).But nowadays there is a fix for that.
But since this is all free (pirated) , people tend to not care about these extremely tiny missing things.In an original version you get everything,but for about 3/4th of pirated games,you get EVERYTHING.I mean 3/4th of these games being pirated are the same as buying them.But the rest are created by clever developers who insert glitches IF you pirate games.But this RARELY happens,even if it does,people ALWAYS find a fix for it.
As for the graphics of Assassin's Creed on your friends computer.,it was not low because it was pirated,some PCs can't handle the high graphics of games like AC2 and Arkham City,that is why it had low graphics .Graphics are almost NEVER affected whether the games are pirated or not.The only things mainly missing are :
a-live content
b-online achievements (such as when you use Windows Live)
People don't really care about this,that's why they pirate games.
!10 points please ? lol