REV. 4.2 pirate hack:
* Faster Uppercuts.
* Jax has a faster Face Smash.
* Jax's Face Smash has Liu Kang's sound FX.
* Cages Shadow Kick goes twice as far.
* Cage has full time Red Shadow moves.
* Multiple Dead Pool Fatality (Normal Uppercut will knock the person in, then you can continue to hit them while they're in the acid).
* Play against Noob Saibot after 6 wins.
* Play Pong on battle 16 instead of 250.
* Fight Smoke whenever you catch the "Toasty" guy (not just the portal stage).

Not confirmed yet but still possible for REV. 4.2 or above
* Secret characters vulnerable to missile weapons.
* Liu Kang has a red dragon fatality.
* Kung Lao has a bones in his hat fatality.
* Baraka's roundhouse has awesome range.
* Mixed ladder, and probably more.