Non-biased review: A great game with many flaws. Very addicting, but not always fun. Read the rest.
The positive: The game has fun and addictive gameplay. You will probably be sucked into this game for a bit, but not as much as games that have multiplayer. There are several new features to the game like better camera angles. There are some new abilities like cloud mario, rock mario, and the new yoshi playability.
The levels are beautifully designed, and the game has one AMAZING soundtrack. A lot of the levels have simple puzzles that can be solved pretty quickly which makes action quick paced. You start out with almost no lives because apparently the game doesn't save lives you've earned, but you can find many along the way. The levels are also well designed, and have some cool features to them.
Co-op mode is increased a little bit, but not too much. Luigi is playable. There is a lot this game has to offer, and there is some variety of gameplay in this game.
The negative: The negatives in this game can get annoying. Camera angles are still troublesome at times. The game is very repetitive where you will see yourself doing some very similar missions, and puzzles over and over again. The puzzles are easy which may be good for little kids, but for older audiences will be a breeze.
The new gameplay elements add very little new gameplay surprisingly. You use rock mario maybe once or twice in the game, and he actually only allows you to roll. Cloud mario is interesting, but all he does is make clouds. Yoshi is fun, but honestly he doesn't really do much accept allow you to have fun running on water. Luigi was most likely tacked on showing as he only allows you to race your own scored.
There are a bit of glitches with AI's. The enemies seem to not be aware of walls so if you are on a high ledge, they will start running into the ledge instead of trying to figure a way up. The squid enemies will sometimes get stuck in a mode where they're charging up a rock for like 2 minutes. A lot of small bugs over all.
Boss battles are entirely too easy, and not even creative. Most of the bosses can be beaten in less than a minute, which I found kind of annoying. The giant snake boss which looked cool, I thought was going to have a hard time killing, like you would have to climb on his back when he dug underground, but no all you do is just punch his red spots. The games bosses are all easy, and a few of them are reused from the last game, which makes it kind of lame. I won't go into anymore details other than the bosses are easier then the normal enemies. Also you fight bowser twice, and you beat him the same way both times, he even has the same attacks both times.
No new enemies really either. Same old same old. So all in all this game is fun and addictive, but I will mention it is by no means perfect, and it seems more like Super Mario Galaxy 1.5. The game also reminds you how to use the controls 24/7. For some reason 3/4 through the game a person tells me a secret where you press 'A' to jump. The game doesn't really seem to be aimed toward players who played the first game. I mean the game acts like you haven't played the last one at all. One last gripe is that your home ship is much less interesting than in the first game. There is almost no exploration to the ship compared to the last, and the person leading the ship has no character at all. In SMG1 you got that one girl whos name I forget, but she actualyl had character. This new guy seems less interesting because he doesn't really have a purpose for helping you. He just is.
Summary: A fun game, that have many enjoyable moments and is a fun experience. Though it has many flaws in it, it doesn't stop it from being a fun game. A must buy for mario fans, and a must buy for people who haven't played the original. If you have played the original than you will realize this game isn't quite a sequel.