If you just NEED a RPG for the DS, are a Mario Fanboy, loved superstar Saga, or just laugh very easy. Otherwise...
This game "babied" you all the way through the entire RPG. All Puzzles were rediculously easy, and then Nintendo even added posters to explain how to do each puzzle..
If you played the first one and beat it with ease, then you will have no trouble with this one. As you are given most of the same moves and puzzle-types as before, and you are given a full tuturial on every move you learn..even if it just requires you hitting the "R" button, it will go into tuturial mode when it comes time to learn a new combo. It it kinda annoying as you can't skip it.
The Bros. Points system has been taken out and replaced with Bros. Items. You can do Bros. type of moves in a sense (not like the link combos from before), but like things such as kicking shells by pushing the button of the character the shell is going to at that moment. These Bros. Items are exactly that though. Items, so they can be consumed. The items aren't really that expensive, and at most points in the game you can return to the Castle (your base in a sense) to restock, heal, etc.
I beat the game at level 30 something. Vs my Level 40 something on the Superstar Saga, despite the fact that "Mario & Luigi Partners in Time" is longer . I don't know if level 50 is max, or they don't expect anyone to get to level 99-100. I mean I found myself strong enough to beat the boss in this game fairly easy at level 30 something. So I guess if you couldn't beat the boss, or do not dodge well then you could level up in a sense to the point it don't matter anymore whether you dodge the attacks or not. I mean the main boss I was fighting, didn't hit higher then a 9 on me... out of 142hp Lugi had and 131hp Mario had. Not to mention all the items you are given throughout your journey. You have plenty of Max Mushrooms (heals you completly), and Ultra Drops (heals whole party 60hp) and even if for some strange reason you used your 30+ of these items you could always buy them at the store for a pretty cheap price for such a good item. You also have Super 1-up mushrooms like in the old game where you can revive you at 100%HP.
Unlike Superstar Saga, when you die on this game, you don't lose that characters turn, which is good, but adds to the already easy RPG system. Their is no Magic in this game (just like the last game), unless you count the Bros. Items.
I don't know, but an RPG just isn't the same without Magic in my opinion.
Overall, even though its not the best RPG, it is the only RPG out for the DS that matters at this point as Lunar: Dragon Song looked promising to start with, but as most of know...it bombed out. You should read the review of that game...losing HP while running...not being able to choose what NPC you wish to attack, etc.
If you compare "Mario & Luigi Partners in Time" to that game, then this game is awesome..but compared to other RPG's..heck for the SNES, this game isn't as good.
Gameplay: Gets real repetitive very fast, especially since you have to dodge the same enemy's attack over and over. Even if you fight a low level monster and your now level 30 (considered high on this game) you still have to dodge their weak attacks or take damage. You can only attack twice in combat at a time, unlike other RPG's where it is usually 4. Meaning you can get outnumbered quick, even if the battles are easy..you have to wait your turn.
Graphics: The Background is better then Superstar Saga and so are the character's faces a bit. But you would kinda expect for the DS to be better then GBA. The Graphics aren't as outstounding as they could be though, for the characters or the background as demonstrated in other games and this games credits.
Sound: I'm not really a sound person. I guess though I would have noticed if it was real repetitive or crappy, but nothing awe inspiring, or even words like GBA Kingdom Hearts had.
Replayability: NONE. You beat it, thats it. No other modes or bonus content unlocked. You save file isn't even recorded as *cleared* as you load your save you will be right before the final boss fight.
If you just NEED a RPG for the DS, are a Mario Fanboy, loved superstar Saga, or just laugh very easy. Then this game is for you...otherwise just wait for a Real RPG to hit the market for the DS.