Sega Smash Pack Vol. 1 Cheats (Dreamcast)

Select Arcade mode. Hold Down/Left + A and press Start at the character selection screen.
A number will appear in the upper left corner of the screen. Use the D-pad's Up and Down
to change this number to the stage you want to be in.

Press Start on Controller Two at the Title Screen to have 2 players play. Note that you
cannot have Player 2 join in during a game.

Press Up, Down, Left, Right at the title screen. A chime will sound. Hold X + Start to
begin game play and choose the stage.

Perform a massive move, and then pause the game during the animation. Choose to restart,
and the move you just did will count on your new game.

Beat the game on the hard difficulty setting. Press B, Left, X, Y, X, Y, B, A, B, A,
Right, Left, Right, Left on controller 4 when the game returns to "Press Start Button"
screen.

Press Start on Controller 2 at the title screen to activate 2 Player mode.

Hold A and Press Start at the title screen. You'll now be able to select the stage, choose
your life, difficulty and reserve lives. To start at the desired level, you will need to
Hold X and press Start at the title screen.

Press X, A, A, X, Down, X, A, A, X at the options screen. A debug menu will appear. 
  Refill Health = Pause game play and press X, A, Right, A, B, X, Down, X, A, Right, B.

Hold Up while Jumping.

Beat the game on easy difficulty setting. Press X, A, Y, B, B, B, Up, Up, Up, Up, Up on
controller 4 when the game returns to "Press Start Button" screen.

Press Up, A, Down, A, Left, A, Right, A, Start, then hold X at the title screen. Continue
to hold A until game play begins. Instead of the normal score and time, you'll see your
co-ordinates and the number of objects on screen. 
  Item Placement = Press A during game play to change Sonic into a game object. Press X to
change into a new object. Press B to place an object on the screen. Press A again to
revert back to Sonic. 
  Invincibility = Sonic is, by default, invincible in debug mode. 
  Slow motion = Pause game play and hold A. 
  Restart = Pause game play and press X. 
  Frame advance = Pause game play and press B. 
  Suicide Sonic = Hold X + B + A during demo screen for Sonic to run into objects and act
strangely.

When you lose your last life, hold X and keep pressing Start. You'll skip through several
screens and continue at the last stage you were on.

At the title screen, hold X + B, Up/Right and Press Start.

Beat the game under the normal difficulty setting. Press L, Left, L, Right, L, Down, L,
Up, R, Left, R, Right, R, Down, R, Up on controller 4 when the game returns to "Press
Start Button".

Highlight the "Shurikins" option and set it to 00. Wait ten seconds and this value will
change to infinite.

Select arcade mode. Hold Down/Left + X + B. Release them and press Start.

At the title Screen, Hold X + A + B, Down/Left and Press Start. You'll be given a menu
that allows you to choose which beast you'll turn into for each stage.

Hold A at when the girl starts to say "Good Luck". Any part of the dialogue script can be
viewed.

Keep pressing B to display the menu and A to close it while holding the D-pad in any
direction.

Pause the game while in the world map by holding Start + A. Keep A pressed to move in slow
motion.