King of Fighters: Dream Match 1999, The

Press A, A + X, A + Y, or A + X + Y while choosing your character to pick a different costume.

When selecting stages in VS mode, holding down the Start button on some stages lets you play on alternate versions of those stages.

At the Character Selection screen, highlight the normal version of one of the following fighters, then hold Start and press any button.

Kyo Kusanagi - Terry Bogard
Andy Bogard - Joe Higashi
Ryo Sakazaki - Robert Garcia
Yuri Sakazaki - Mai Shiranui
Billy Kane - Orochi Yashiro
Orochi Shermie - Orochi Chris
Omega - Rugal

Press X + Y while the game is paused.

Highlight one of these on the Character Select screen: Andy, Billy, Chris, Joe, Kyo, Mai, Robert, Ryo, Shermie, Terry, Yashiro, or Yuri. Next, press X while holding down Start to select your characters alternate costume.

Hold B when selecting the fighter before a match. The faces that appear should be smiling or normal for each fighter for the cheat to work. If an angry face shows up, the trick doesn't work. Now, when you playing and your characters is stunned or held by the opponent (eg. Joe's throw, King...), hold X + Y + A and one of your teammates will jump in and help the your fighter.