TWEWY has its flaws, but given the amount of care put into it, it stands as one of the best handheld games ever created.
I will not mention plot details so that when you play it, it will suck you in with its heartfelt, realistic characters and wonderful, immersive setting without having to spoil anything. I will just say that the plot of TWEWY is one of the most involving, intriguing, and affecting stories I have ever experienced on a handheld system, or ANY gaming system, for that matter.
The gameplay is very refreshing, and it spices up the monotony of the average Action RPG, where most of the gameplay involves smashing buttons until you win. In TWEWY you are required to strategize, and even if you level grind and you play on the easy difficulty setting (btw the game allows you to switch between difficulties in game, which is awesome), it still isn't a cakewalk. The only problem is that some of the powers you use in combat get mixed up because some of them have similar touch screen input commands. It doesn't happen too often, and even if it does it's really not a huge issue if you know what you're doing.
The graphics aren't as technically impressive, as, say, Final Fantasy 3 or 4 for the DS, but I can certainly tell you they are much more colorful and more immersive than either of the games I mentioned. Shibuya is a positively remarkable sight; it is crowed with citizens and shops and monsters and style. You really need to see it to believe it. One thing I need to mention though is that going around the city completing objectives can be confusing because there isn't a clear map; even by the end of the game you still will have some trouble navigating around the city because it's so large.
The soundtrack is probably the most unique thing about TWEWY, as it has multiple genres in the mix-hip hop, techno, rap, metal, even one 8 bit song. Almost every song in the game is great, although the soundtrack tends to loop way too much. Even then you hardly notice because it is so great.
The game will probably take 15-20 hours on the first try, but there is a very good reason to play through the levels again to complete specific objectives so you can unlock the "true" ending of the game. Not to say the ending to the main game sucks or anything, it's just the while it does give off emotional impact, it's too vague. It leaves out some things some players might want to find out. For those people...enjoy the extra 10-15 hours of game.
Rarely have I played a game that actually tries. TWEWY is not just another Final Fantasy spin off (like we just CAN'T get enough of those), or other Kingdom Hearts, or another failed pet project. It's not some little thing the developers over at Jupiter did to rake in a few bucks. It was clearly a game that they took great time developing, and it shows. The fact it doesn't have some fancy franchise to hang on to and it stands on its own the way it does is frankly awe-inspiring. Is it perfect? No, but what kind of question is that? Of course it's not perfect, but I do not know of a single game that is. Whether or not it's perfect is irrelevant; TWEWY is a fantastic RPG that absolutely everyone with a DS should play and it is, in my opinion, one of the most well crafted handheld games ever made.
Please, buy it and enjoy it so we can hope for the slim possibility that Square Enix will stop milking the FF cow and give us a sequel or at the very least a spin off. Trust me, you won't regret the purchase.