It has been well documented that the Johnny Cage character was inspire by Jean-Claude Van Damme. During a fight you can see Johnny Cage perform Van Damme's signature helicopter kick.
There is a scene where two fighters compete with each other in breaking anvils. This is a reference to the "Test Your Might" mini-games in the Mortal Kombat games, where players tested their strength on blocks of material, of increasing hardness (wood, stone, steel, etc).
Scorpion in the WB logo at the beginning was producer Rick Morales's idea. He originally intended Scorpion to pull Daffy to him with a kunai through the head.