It's still a solid title but plays it too safe.
The thing is NSMB2 is not a bad game by any means and while I wished it had experimented a bit more, I still had fun playing it. If you watched the Game Overthinker's recent episode about Mario, I share most of the same feelings. I'd rather Mario play it safe and be good then wallow in crap like Sonic, Crash and Spyro did (yes Sonic's improved recently).
So the premise of this one brings back the Koopalings. Clearly realizing that no one liked Bowser Jr. The koopalings tie him up and lock him in the closet, steal the keys to their dad's Clown Car and go to kidnap Peach and wreak havoc (well the locking BJ in the closet was my personal fantasy there.)
The gameplay is what you expect from Mario. Run, jump, use items, etc. The racoon leaf is brought back for nostalgia and for some reason this manifests itself with Luigi having a fox tail instead of the same racoon tail as Mario (is this a reference to Tails?) What's a tad disappointing is the game didn't carry over some of the things that NSMBWii introduced such as Yoshi, the penguin suit or the helicopter hat. Though Racoon tail > heli hat.
The other big addition is the accumulation of coins in that the game does a grand total of all coins collected. Coins come out of pipes. There are gold rings that turn everything to gold and the one new item is a gold flower that not only destroys everything but turns it into coins. A feature that is available is "Coin Rush" where you basically play 4 stages with a shorter time limit with the goal to collect as many coins as possible. This you can use the Street Pass feature and compete with others for high scores. And truly I had fun with this. In NSMBWii I had this urge to collect as many coins as I can just because I could and now it actually means something. Though with such a focus on coin collecting, it renders the life system useless. Seriously why not get rid of lives altogether or at least eliminate the 100 coins= extra life. Sonic Colors did that. Has anyone seen the game over screen in the main story?
Though unlike the first DS game collecting all those star coins feels more worthwhile. Star coins unlock paths on the map as well as 90 will get you to the final world. The main game is only 6 worlds long but bonus Mushroom, Flower and Star worlds are unlockable as well trying to find all hidden paths.
Is this a ground breaking Mario title? No. Is it a solid 2D platformer. Yes. Don't set ridiculously high standards and you'll have a good time.