-The wallbounce/overheads
-Elective armor
-Hit confirming an EX
-NO CLASH
-Online leveling
-Player Cards

My Number 1 vote would be Practice Mode, was done a lot better this time around.

I freakin' love the level-up unlock method. I wanna see something similar in fighting games altogether.

Killer Frost super as Sub Zeros Fatality, thats all.
Besides what I mention, I hate everything about this game honestly, sad thing is that they will put something from this game to the new MK, you can count on that.