SPOILERS
Yes the star coins are used like in NSMBW, where you need them to unlock levels in the special world after beating the game. The special world is also shaped like a star in homage to another Mario game's special world....
SPOILERS END

I beat the game last night. It's wonderful and it's my favorite game in the NSMB series and one of my favorite games in the Mario series overall.

There's been some concern about reused music, but while there are several reused tracks, the colorful, crisp backgrounds overshadow the reused music. There are even remixes of the tracks when using baby yoshis or playing in Frosted Glacier too, and the original NSMBU ground theme and athletic theme are used fairly well as well. The final Bowser battle does have new music, thankfully.

@DestinyMan, so the game had a good finale? I heard the last few levels are creative. (No spoilers please)

So the final Bowser battle music is new, check. What about the credits theme? Still the reused credits from the Wii game or no?

Hmm so I already knew this game would be the best NSMB, but one of the better Mario games overall?

The boss battles seem REALLY creative off the bat so
I wouldnt be surpised if even world 8 and (is there a world 9) world 9 were extremely creative.

@Emaan: The credits music is new too.

Without spoilers, I can state that I think the final Bowser battle is the best one in a while, better than the one in NSMBW or NSMB2. Some things are typical for a final Bowser battle, but there are a couple of cool twists too. The battle is overall more engaging. Some think it's easy, but it's actually tricky if you have no power-ups and stay as a small character. I died to Bowser several times before I finally got him.

I have to wonder why they didn't include online play. Again. Time to step up, Nintendo.

Probably because they'll add it to a mario game in the future, plus they have to figure out how to implement it into a game such as mario, it might not be exactly what you'd expect, so don't keep your hopes up too much.

@DestinyMan, that's good. I was hoping for a good final Bowser battle + ending.

@DestinyMan
Yeah, cool to hear that the Bowser battle is snazzy. I just finished NSMB2 yesterday and it's Bowser battle was worse than NSMBW, but miles better than the original New Super Mario Bros. Super Mario 3D Land probably has my favorite Bowser battle yet, but we'll see when I get to play this game.

I beg your pardon, but have you even played Super Mario World?

Edited for accuracy. :3

Super Mario World's was cool, but a little easy and Luigi's Mansion had King Boo in a Bowser costume so that doesn't count.

It's brilliant yes but is it worth paying over £350 for a Wii-U just to play this game as thats all I'm interested in out of all the launch titles. Now I don't think so.

I am still keeping my pre order but when I recieve my zombiu package, I will sell it online for a big profit. I will then wait until some more Nintendo A+ titles come out. Hoepfully by then it should come down in price.

Super Mario World had such an epic final battle. You're on top of a castle...there's thunder and lightning...Bowser's flying Koopa-clown car is looming over you....Peach appears crying "HELP!"

All to some adrenaline-rush final battle music.

If it also counts. Yoshi's Island had an incredible final battle with Baby Bowser.

Yoshi's island doesn't count, because no words can describe how awesome it is. :3

Can it possibly be topped?

How could I forget the Yoshi's Island boss? Hands down one of the most epic boss fights ever in my eyes.
The original Mario bros gets some credit for having Bowser be an actual threat though.

Alrighty,we're getting off topic here.

Back to everyone telling me how awesome NSMBU is.

</3

Well let's see:
-It came unexpectedly
-it has it's own well executed gameplay mechanic
-The sense of urgency is there
-it plays hardcore, awesome music
-It still holds up graphically

I can go on and on about it, but I'll just stop here.

I think it was a nice touch to have the Propeller and Penguin Suits come back in the Special World, though with the Flying Squirrel Suit i'm not sure how much I would notice they were missing anyway.