Rented it. Buying it. Read on to find out why.
Graphics: Incredible. Best graphics I've ever seen on DS. Beautiful cutscenes and play.
Control: Great. Love the control, waaaay easier than in previous Metroid Prime games. Only problem, no lock-on. But charged shots do change trajectory if target moves.
Sound: Awesome. Very sci-fi, and lets you know what's going on. Also, fantastic music.
Play: Great. Not too hard, but not easy either. you have plenty of Boss fights. only problem, you have to flee the scene every now and again. Learn your maps and you're fine though.
Multiplayer: Wonderful. I've only gotten to use single-card Deathmatch, but that's a blast (no pun intended). You get to unlock new characters to use. You have 12 levels! And lots of weapons, and you can set time limits and point limits.
-----
PROS:
-Beautiful presentation, audio and video
-Great control
-Cool bosses
-Morph ball puzzles!
-Mystery
-Doesn't kill your touch screen
-You can watch your cut-scenes later too
-It actually tells you why you have to shoot doors!
-You can unlock new hunters by defeating them in Single- OR Multiplayer
CONS:
-Sometimes you have to die in order to figure out what to do
-You can't save until you reach a save point
-Sometimes in Multiplayer, the frame rate slows down
-You probably won't scan it all the first time around
-Some rooms seem similar to other rooms (but they are different)
-----
I love this game. I would strongly suggest it if you're looking for a good game. I haven't been bored or frustrated since I started. It's also fun to try out the different characters in Multiplayer.