So the NSMB series was a series of platformers which while had their merits, failed to innovate as time went on and left them in a void in which the game just exists and nothing more. I did mention that NSMB DS and Wii were some of my favourite titles in the series, but this game is where the NSMB series truly fell from grace.
So long story short, Koopalings kidnap Peach (again) and the Mario Bros have gotta save her.
There are 8 worlds (2 of them are World Mushroom and World Flower for some reason...) to conquer, each with their own Koopaling to fight. The Raccoon Leaf returns to NSMB2 alongside the new Golden Flower and Golden Shroom. The latter two power-ups serve as the new game wide gimmick; Millions of Coins. hooraaaaaaayyyyyy... On the title screen, there is a Coin Counter that shows how many coins you have picked up via main campaign or the DLC packs. Getting 1 million of them equals an extra title screen. It's not worth the hassle though, so don't bother with it.
Honestly, there isn't much else to say about this game, as it basically follows the same formula that the previous games did. My problem is that the game is much shorter than the previous games and does almost nothing to improve the series. NSMB DS was a fresh return, while Wii had power-ups, Yoshi, local co-op etc. But NSMB2 besides the Coin gimmick is more of the same and quite frankly what has been offered is an underwhelming package.
New Super Mario Bros 2, in my opinion, is the worst game in the NSMB series. It doesn't do much if ANYTHING to improve the formula of the series and while what is there works perfectly fine, it is just an underwhelming game compared to the previous ones.
Side Note: I haven't played NSMB Wii U as of this review, and even then I don't have high expectations for the game.