Actually: (why am I replying to this like a year later wtf self? Also nitpicky: the first game came out in 2002! KH2 was the one from 2005)Cons: IT'S KINGDOM HEARTS!!! THERE ARE NO CONS!!!!!
-Lag. I had a decent amount of lag when opening menus/cutscenes/minigames/new areas/etc. I dunno whether this is a "my PSP is old" problem or a general problem.
-The plot can be kinda (very) confusing if unfamiliar with the series.
-Also sometimes the voice acting (hi Terra) can be a little...off.
BUT ANYWAYS ON THIS NOTE HOW ABOUT I TALK ABOUT:
Kingdom Hearts 3D: Dream Drop Distance
+The graphics are gorgeous! I didn't know what to expect graphics-wise when I started but the opening cutscene (and everything in general) blew me away.
+The voice acting is rad.
+It does something utterly wonderful and has little summaries of previous games when they become relevant. So it's pretty helpful to those who've never played before!
-That being said, it's pretty fucking weird and (I presume) has a better effect when played after the other games, especially in terms of plot twists.
+Speaking of plot twists! There's some pretty good ones in here.
-I dunno how I feel about some of the execution though; since I spoiled myself before playing the game, I had expectations of how certain plot twists would go (or, rather, if they'd even be stated; stuff about Riku from the first game or Saix, for example, hadn't been on the plot summary I read so I expected them to just be implied, but they were actually outright stated, and I had mixed feelings about this)
+The Dream Eaters (your allies, and also the enemy kinds) are adorable for a video game series in which people's hearts get stolen by evil creatures of darkness who sometimes possess your enemies/friends.
+/- Unfortunately the naming system for said allies has a censorship thing going; you can't name your Dream Eaters anything inappropriate. Which results in a massive fail on the devs' part because they accidentally made one of the Dream Eaters' default names unable to be used. The optional plus on this is because a) younger (misguided) kids might be playing this and b) this is greatly amusing to an extent. (Until you accidentally spell the nickname wrong and-oops that's just me. Poor Porcuoine.)
+/- The gameplay is definitely different, because you switch player characters with barely any notice (for story reasons). Plus or minus because it definitely takes some getting-used-to and some people probably hate it.
- Some of the bosses (cough cough Chernabog and young 'nort) are a pain in the ass to beat, usually because of a gameplay gimmick. (Chernabog took me three tries to beat, and 'Nort didn't kill me but he took probably like twenty minutes because of the damn gimmick)
+ The soundtrack is absolutely lovely.