SNK vs. Capcom: SVC Chaos cheats and cheat codes for XBox

Unlock Dan
Hold Start and push Down, Left(7 times), then any button at the title screen.

Unlock Demitri
Hold Start and push Right, Right, Right, Left, Up, Right, Down, Up, then any 
button at the title screen.

Unlock Evil Iori
Hold Start and push Up, Up, Up, Down, Left, Right, Down, Left at the 
title screen.

Unlock Geese
Hold Start and push Left, Left, Left, Down, Left, Up, Right, Up at 
the title screen.

Unlock Goenitz
Hold Start and push Down, Down, Down, Right, Down, Left, Left, Left 
at the title screen.

Unlock Mars Alien
Hold Start and push Up, Down, Right, Right, Right, Up, Down, Left, 
Left, Down, then any button at the title screen.

Unlock Shin Mr.Karate
Go to the fighter selection screen, then highlight Kasumi and hold R trigger.

Unlock Super Akuma/Shin Gouki
Go to the fighter selection screen, then highlight Balrog, then hold R trigger.

Unlock Violent Ken
Hold Start and push Up, Up, Down, Left, Left, Right, Left, Up, then any 
button at the title screen.

Unlock Zero
Hold Start and push Up, Right, Right, Left, Left, Down, Up, Up, Up, then 
any button at the title screen.

Unlock Red Demon
Beat opponents until you have to fight with Red Demon in survival mode. 
Beat him to unlock him as playable character. Highlight Tabasa at the 
fighter selection screen, then hold R and push X, Y, A or B buttons 
to select him.

Unlock Young Athena
Beat opponents until you have to fight with Athena in survival mode. 
Beat him to unlock him as playable character. Highlight Genjuro at the 
fighter selection screen, then hold R and push X, Y, A or B buttons 
to select him.

Unlock art gallery
Finish the game in survival mode and beat 36 fighters to get access to 
the "Art Gallery" option.

Secret characters:
Go to the character selection screen and hold R over the four top fighters
of the inner most rows of both sides. You can access to the following 
characters by holding R while on the standard character's location at 
the selection screen:

Chun Li: Demitri
Dhalsim: DaN
Kasumi: Shin Mr. Karate
Kim: Evil Iori
Kyo: Geese
M. Bison: Violent Ken
Ryo: Goenitz
Ryu: Zero
Terry: Mars People
Vega: Shin Akuma 

Two Hidden Bosses:
Defeat 35 fighters in survival to unlock Athena and defeat 36 Fighters 
to unlock Red Arremer. Then hold the R button over Tessa to use Red 
Arremer and hold the R button over Genjyuro to use Athena.