OK... my wife is the Mortal Kombat fan of the family, and the fighting game fan of the family. So this should really be her review... because I'm just going to trash it.
The problem here is plot, as in they actually tried to add in a real plot. Mortal Kombat is a fighting game. You play it to peacefully beat your friends to a bloody pulp... and that is where the fun is.
But they added a plot.
In Twister, the star of the show was the tornado. The plot was there to move the view from tornado to tornado. And in Back Draft, it was the same... with fire.
Mortal Kombat thought it had to be deep. It thought it had to be something more than it a tournament. It thought the characters had to have more than surface level depth.
THE DIDN'T.
The Tournament should have been the star. The plot should have only been there to move you from fight to fight with a climax that shouted "FATALITY!" and left it at that.
Instead they tried to add depth where no depth was needed... and that killed the fun of Mortal Kombat.
Not every movie needs to have a plot and characters, some movies work best as mindless popcorn munching escapism.