iDOLM@STER 2: great, but missing some features
If you've played iM@S1 or any of the iM@S SP games, you know what to expect from an iM@S game, though iM@S2 expands on the gameplay in many ways. There is now a currency in-game (literally just called "money") which you use to buy accessories and clothes for your idol, as well as pay for daily scheduling -- going to auditions/festivals/lives, promotions and paid promotions, lessons and super lessons, and going shopping. You have to take the different regions of Japan and the fans' awareness levels into account, and until you get the hang of it in your first 2 or 3 playthroughs, this game is rather difficult, but it's very fun.
You can only produce trios (you do -not- produce solos, duos, or quintets), excluding the use of Iori, Ami, Azusa, and Ritsuko. In the included Stage for You! Mode (similar to L4U), however, they can be unlocked about halfway through your first playthrough.
The hardest things to unlock are some of the colors/costumes/accessories you can buy. Some of the recolors alone cost up to 500,000 money, and there's even an accessory that costs 999,999 money. Put your gamer face on, because that requires a -lot- of playing.
The main downside of this game for me is that the game no longer has a Part Select -- that is, you can't choose which idol sings which lines in a song. The pre-stage camera control is also gone, which only leaves a hard-to-control camera system during the stage, similar to SP's. On top of that, the auto camera is -very- predictable (especially in "The world is all one!!"); it does the same thing every time you play, and it -always- points in the wrong spots (i.e. closes up on an idol that isn't singing).
There are also only 4 included songs that you can use with quintets, 3 of which are available from the start. On top of that limit, there are only 4 stages that support quintet performances.
Overall, iM@S2 is an enjoyable game, and has a lot of replay value to it (especially if you want to complete your clothes/accessories collection). But if the stage customizability and performance directing was left in the game, as well as more freedom with quintet performances, the game could've been a 5/5.