It also has a cool team battle mode which is accessible with a code. When you uppercut your opponent into the pit in the Pit II stage, the background will rotate slightly before the opponent hits the ground the rotating movement was not present in the arcade version. The SNES port also added some features that were not in the arcade game.
Sure, some small things like the opening story art and the pillars in the Portal stage are gone, but it is still excellent.
I'd say Mortal Kombat II is the best SNES port because it has nearly everything that the arcade version had.