NSMBW marks the return of the Koopalings to official 2-D Mario platformers (in between this game and Super Mario World, they were in Hotel Mario and Mario and Luigi: Superstar Saga and were going to be in Super Princess Peach). Also, this marks the first time they appeared alongside Bowser Jr., and many people were happy for that, too.
Not to mention, Yoshi, Kamek, the difficulty... hell, there was practically a new one every time a new preview went up.
The return of the non-tanooki Raccoon Tail (pictured above) is this for both nostalgic value (as it's even more iconic than the 3D Land-featured Tanooki Suit) and gameplay value (it doesn't simply slow your fall this time, it flies).
The flying powerup's comeback comes alongside the obligatory P-Charge bar, on the bottom-left corner of the screen as it was back in the Super Mario Bros. 3 days.
Luigi was confirmed to be in the game on Nintendo's Facebook page almost as soon as the game was fully revealed. This implies that the game is reaching the end of its development pretty fast.
Luigi is unlockable in Single Player mode.
This game was released at retail and the Nintendo eShop simultaneously, making it the first major Nintendo title to ever have a digital release.
Okay, the game is out, now why there's a notification in my 3DS... okay, Nintendo's bragging about the game's success like last week, players worldwide have collected a grand total of 100 billion coins, Blah Blah Blah... wait, what? Did you just say you re-opened all the Toad Houses as your way to celebrate this? Wow — of course, the fact that Toad Houses being open is tied to Nintendo's decision isn't that great — but still, that's awfully nice of you! Thanks!
They did it again for the 300 billion coins, but maybe they can give us more than... what's this, "Golden Classic Course Pack"? Wait, is it... a Nostalgia Level pack given away for free?! And the three levels featured are, in order, Super Mario Bros.' 1-1 (with 1-2 as its underground part), Super Mario Bros. 3's 1-1 and the first castle (1-4) from Super Mario Bros., thus giving us the chance to face Bowser without having to face the Final Boss?!? We'd say "take my money, Nintendo", but this is given away for free... and it's available until February 2013!!!
The first player can finally play as someone other than Mario.
The announcement of the possibility of more characters, a power up selection that rivals Super Mario Bros. 3 (which means the game may have at least 8 different power-ups), and the option of making co-op players intangible to one another. However, the extra characters and intangible feature did not make it into the game.
Time Attack mode finally makes its official game debut in the Mario series!
The world map, akin to Super Mario World (sort of), is now shared between all worlds. In other words, every world map is stuck to the next one and shares the same screen. Sure, it feels a bit "forced", as the whole thing now looks similar to a patchwork, but still, it's a very nice touch indeed.
The "Boost Rush" mode. Every level is now a Fixed Scrolling Level, and it speeds up as you collect coins. Levels will get very crazy this time.
The confirmation of this game coming out at launch, making it the first major Mario launch title since Super Mario 64.
All of the Koopalings now have wildly different fighting styles, which pleases people considering that their battles in the last two games were both easy and similar. For example, Iggy's battle has him running on the ceiling and summoning lava monsters.