Infinite Koins
Retrieve a necklace from a dead person at the G-1 map location. Take it to the house at E-8 on the map (in Edenia) and speak to an old man. He will trade you 500 platinum koins for the necklace. Once you've made the trade, return to the carcass and another necklace will appear. Grab it, return to the old man and sell him the necklace again. Repeat this process over and over to get an infinite amount of platinum koins.
Unlockable Characters
This title features a number of hidden characters that you can unlock by finding treasure chests on the map. At midnight on Fridays, open the chest behind the tent at G-8 on the map to get Liu Kang. Find the chest at H-2 in Earthrealm between the hours of 7 p.m. and 9 p.m. for Kira. Find a chest at A-3 in Outworld between those same hours to unlock Tanya. Earn Keshi by getting the chest at E-4 in Earthrealm. Head to the chest at H-4 in Chaosrealm to unlock Havik.
Unlockable Arenas
You can also open up new arenas in which to fight by finding treasure chests in the game. Play in Dragon Mountain by opening the chest at H-8 in Outworld. Get the treasure chest at A-4 in Orderrealm to unlock Kuatan Palace. Open a treasure chest at H-5 in Orderrealm to access Quan Chi's Fortress. Look inside a house at D-7 in Chaosrealm to fight in the Dragon King's Temple.
Scorpion Snare
You can use a glitch in a level to your advantage. Choose Scorpion and fight in the Beetle Lair level. When you stand in a spot on the stage where stained glass is between Scorpion and your opponent, you can automatically snare him with your spear, even if he is using the block maneuver. Your foe will be held in place by your spear tether until you attack him.