Here are a few things I didn't expect from this game:
Spoiler Below - When a harmful projectile such as rolling spiked balls hit walls and fall offscreen, they're not rendered "dead"--they will still hurt you as they fall.
- Standard enemies do not "pop" from Yoshi's stomps as they did from SMW. But you can still bounce off spiked or otherwise harmful enemies without harm.
- A new swimming move has been added: the flutter kick. Hold the swim button while underwater to slow your descent.
- You can KO a shelled enemy instantly with a ground pound. In NSMB, they just slid off if you did this.
- The spinning drill stomp from NSMB is cancelable; release the down button to stop yourself. On a side note, the ground pound is also cancelable; press up while you're dropping to return to normal gravity.
- The Lakitu still leaves behind its cloud when you stomp it; in previous games, stomping KO'd the Lakitu but dissolved the cloud.
- Fuzzies (the black ones) are vulnerable to fireballs.
- Giant Goombas split into two normal ones when you stomp them.
- Lemmy Koopa's circus balls are harmless to the touch. The only danger they pose is bouncing you into other dangerous things.