I've played it a little bit.
Basically, the reviews are sort of right. It's *fun*, but it's *NOT* a Mana game, at least in the traditional sense. That aspect disappointed me greatly. Here is the basics:
You start out by picking one of four characters. This is the *only* character you get throughout the whole game (so no, the others don't join your party - you can't even have a party). I forget the names, but there is a guy, a girl, a sprite, and that rabbit guy from Legend of Mana.
The game is *extremely* mission-based. It will be something like, "Oh no, something is happening at the Mana tower!" and then you'll go to a non-interactive world map, click on "Mana Tower" and then you'll be in the dungeon. You go floor to floor, fighting monsters and collecting little mana sapling things (I forget the exact name) which is a fancy way of saying "key" to the portal ("door"😉 to the next floor. After like 10 floors, you fight a boss. Some more story ensues, and then you are off to another location that is pretty much identical except for the terrain and monsters.
There are also "quests" you can do, which is like "kill all the rabbites" where you will go back to a previously beaten dungeon, and they will change "boss" floor into a random monster floor based on your quest. I think there are also "get X item" or something quests too, I dunno. Then you get a reward (item, money, etc) for doing that.
You get to carry along *one* spirit with you (i.e. Undine, Wisp, Salamander, etc etc) which can do either a "helpful" (i.e. Secret of Mana girl magic) or "attack" (i.e. Secret of Mana sprite magic) spell. You get so little MP that these guys are basically worthless. Bring Wisp along and just use him to cure yourself ;p I am playing the main guy, so maybe if you play the girl or sprite characters you get more MP and magic is more imporant. I dunno. No idea what the rabbit guy does. You can swap out spirits in between dungeons, and you can *only* swap equipment when you are not in a dungeon (gay).
There is also a "stone" system where you basically get a 4x4 grid and you can put different stones in there for like +1 ATK and crap. It seems largely pointless. Like, I thought maybe I'd get some kind of bonus for having say, all red stones. Nope. You can "equip" some extra attack moves (like I got a sonic wave attack) through this, but otherwise I don't know why they really bothered.
Like I said, the game is not *bad* persay, but it's just so disappointing and not nearly as good as I thought it would have been. I havn't really played it since the first day I got it (Nov. 1st) because I'd rather play FFXII/FFV, etc. From what I hear, it's really short - like 5 or 6 different dungeons. Then of course you could play quests and stuff I guess but that seems pointless.