In regards to gamplay, X-2, no question. But, overall, I preferred XIII-2. Although I disagree that it was as silly as X-2. X-2 started silly and got more serious towards the end. XIII-2 just has moments of levity. There's actually quite a lot of dark, serious stuff in there. Coping with the loss of a loved one, the horror of a society gone wrong, loneliness, the illusion of choice... Sure, there were a fair few light moments scattered in there, but the overall tone was pretty bleak.