Anyone know its length? I've heard it was great, but was short. Is this true?

I've heard the same, about 20 hours long to complete te story.

I'm in the second world now, and so far I'm not very impressed. The game feels like a dumbed down BBS to me, and the story hasn't started either. I really hope things will pick up from now on!

wow... i feel completely the opposite!

I posted these impressions on another thread about the game but the thread pretty much died:

I'm playing this game at the moment and im very impressed. Not only are the worlds bigger, the combat better (with flowmotion and spirit combos) as there is a whole pokemon game within the game with tournament 3 on 3 battles aswell. You use cards to battle with the monsters on the colleseum mode and can battle other players through wireless.

Leveling the spirits is also something you want to do as it unlocks many of the special moves and skills.

I'm more than 5 hours into the game and im still on traverse town. So far its better than i thought and shaping up to be the best entry in the series.

The only thing some people might not like, but i think its a real improvement over BBS is the drop system. You will be forced to switch character every now and then. You can get skills to delay the switch timer and you can force it your self anytime you want. The thing is, this way it doesnt feel like a grind and the leveling is shared between your two characters (wich was a pain to start over everytime on BBS). Also, like BBS each character has acess to some exclusive areas and both have thier own sets of treasure to find.

Seems like the second 3rd party hit on the 3DS, after RE revelations.

Today i have hit 8 hours and backtracked to get all the treasure chests on traverse town and had a few more 3 on 3 battles tournaments with my spirits. I had time to take a sneak peak at the grid (tron:legacy) and it looks amazing. Definitly enjoying the game loads.

There is one bad point that i already got used to, wich is the camera. I dont have the CPP, so i have changed the controls to type B just like i did with BBS (aka one button to reset the camera behind your character). The camera reset is a bit unnatural, but i got used to it as i have to stop movement of my character momentarely before i reset the camera, otherwise its gets a bit spinny and difficult to track (for referance the camera isnt worse than any other KH game, it just gets more stressed here because flowmotion speeds up the action considerably).
Easy to overlook with such a fun game though.

@nem: how come you are spending so much time in Traverse Town? I finished it in ~1.5 hours

Is it easy to follow the story if you can't remember Kingdom Hearts 1 or 2 very well? xD

So far things have been really confusing, but I think things will clear up. There are also a lot of flashbacks to keep your memory fresh.

I could do the opposite question. Did you read all the tutorials and flashbacks. I also look every nook and cranny for treasure in every area and spent some time with my spirits patting and playing some mini-games with them aswell as some tournaments. I  finished with both characters and it took a bit above 5 hours but less than 6. It turns out i was at the ending of that world when i made the first post about it.I also replayed the dive sections for a better score.

The story is easy to follow if you're new to the series, but if you're familiar with the series it gives you more for every detail. For the record though, this game feels alot like kingdom hearts X Pokemon. People who like pokemon/AI simulation mini-games like the chao os Sonic adventure for example, will love this game. You can even change the color of your spirits by shooting color balls at them, and theres definitly a drive to catch/create them all so you unlock every skill.

As for game length, BBS took me 50+ hours to beat with all characters and special ending. I am thinking this one will land at about 40+ hours. Normal fair for an RPG, and especially considering they made you grind the levels all over again with each character. If you rush everything and dont care for any mini-games and character development, you will probably be able to beat it in 20 im guessing. If you did the same on BBS im pretty sure every character would be done in under 10 hours for comparison.

The store I ordered it online from are having stock issues so I won't get my copy for a while. Funny how pre-ordering a game serves little purpose these days.

Sounds about on-par with other entries. I beat KH2 FM+ in 16 hours.