Old stuff for the UMK3 emulation on your MKA disc:

Hold LP, BL, LK, RN, and joystick DOWN + LEFT (P1, DOWN + RIGHT for P2) will change Robot Smoke into Human Smoke.

Press the HP, LP, BLOCK, LK, HK keys on the following controllers the listed number of strikes to unlock the hidden kombatants in UMK3 (Arcade). You can only do this on the game over screen (not the pre-match VS screen). Note that you can hold UP on your joystick and press the difference between ten and the listed number (i.e., if you need to press something 8 times, you can hold UP and press that key twice instead).

Mileena
P1: 2 - 2 - 2 - 6 - 4
P2: 2 - 2 - 2 - 6 - 4

Ermac
P1: 1 - 2 - 3 - 4 - 4
P2: 4 - 4 - 3 - 2 - 1

Classic Sub-Zero
P1: 8 - 1 - 8 - 3 - 5
P2: 8 - 1 - 8 - 3 - 5

Press the LP, BLOCK, LK, keys on the following controllers the listed number of strikes on the pre-match VS screen for various effects (UMK3). Note that you can hold UP on your joystick and press the difference between ten and the listed number (i.e., if you need to press something 8 times, you can hold UP and press that key twice instead).

Throwing Disabled
P1: 1 - 0 - 0
P2: 1 - 0 - 0

No Blocking
P1: 0 - 2 - 0
P2: 0 - 2 - 0

No Power Bar
P1: 9 - 8 - 7
P2: 1 - 2 - 3

Psycho Kombat
P1: 9 - 8 - 5
P2: 1 - 2 - 5

Infinite Run/Combo time
P1: 4 - 6 - 6
P2: 4 - 6 - 6

Random Kombat 1
P1: 4 - 6 - 0
P2: 4 - 6 - 0

Random Kombat 2
P1: 4 - 4 - 4
P2: 4 - 4 - 4

Dark Kombat
P1: 6 - 8 - 8
P2: 4 - 2 - 2

P1 Low Life
P1: 7 - 0 - 7
P2: 0 - 0 - 0

P1 Half Life
P1: 0 - 3 - 3
P2: 0 - 0 - 0

P2 Low Life
P1: 0 - 0 - 0
P2: 7 - 0 - 7

P2 Half Life
P1: 0 - 0 - 0
P2: 0 - 3 - 3

Galaga Before Match
P1: 6 - 4 - 2
P2: 4 - 6 - 8

No Sound Kombat
P1: 3 - 0 - 0
P2: 3 - 0 - 0

Fast Uppercut
P1: 7 - 8 - 8
P2: 3 - 2 - 2

Explosive Kombat (2V2)
P1: 2 - 2 - 7
P2: 2 - 2 - 7

Explosive Kombat, No Throws (2V2)
P1: 0 - 2 - 2
P2: 2 - 2 - 0

Winner Of R1 Fights Motaro
P1: 9 - 6 - 9
P2: 1 - 4 - 1

Winner Of R1 Fights Shao Khan
P1: 0 - 3 - 3
P2: 5 - 6 - 4

Winner Of R1 Fights Smoke
P1: 2 - 0 - 5
P2: 2 - 0 - 5

Winner Of R1 Fights Noob Saibot
P1: 7 - 6 - 9
P2: 3 - 4 - 2

Stage Select: Subway
P1: 8 - 8 - 0
P2: 0 - 8 - 8

Stage Select: Street
P1: 0 - 7 - 9
P2: 0 - 3 - 5

Stage Select: Rooftop
P1: 3 - 4 - 3
P2: 3 - 4 - 3

Stage Select: Khan's Tower (Bank Rooftop?)
P1: 8 - 8 - 0
P2: 2 - 2 - 0

Stage Select: Bridge
P1: 0 - 7 - 7
P2: 0 - 2 - 2

Stage Select: Soul Chamber
P1: 1 - 2 - 3
P2: 9 - 0 - 1

Stage Select: Bell Tower
P1: 0 - 9 - 1
P2: 1 - 9 - 0

Stage Select: Kombat Temple
P1: 6 - 0 - 0
P2: 0 - 4 - 0

Stage Select: Graveyard
P1: 6 - 6 - 6
P2: 3 - 3 - 3

Stage Select: Pit 3
P1: 8 - 2 - 0
P2: 0 - 2 - 8

Stage Select: Noob's Lair
P1: 0 - 5 - 0
P2: 0 - 5 - 0

Stage Select: Scorpion's Hell (Netherrealm)
P1: 6 - 6 - 6
P2: 4 - 4 - 4

Stage Select: Jade's Desert
P1: 3 - 3 - 0
P2: 0 - 3 - 3

Stage Select: River Kombat
P1: 0 - 0 - 2
P2: 0 - 0 - 3

Stage Select: Khan's Kave
P1: 0 - 0 - 4
P2: 7 - 0 - 0