MK vs. DC is not worth a purchase.  But it is worth a rental if you’re a fan of fighting games or of the Mortal Kombat lore.  I got it for extremely cheap.  The story is alright, nothing special but it’s not horribly bad.  The graphics should’ve been better considering they were based on the Unreal Engine 3.  They didn’t make good use of neither Mortal Kombat nor DC art styles.  Both have looked better before.  The simplified gameplay is also a negative.  The game also wasn’t bloody enough for Mortal Kombat.  That being said, what’s there isn’t wholly bad or very good.  It’s an extremely average fighting game.