You can use one of the following cheat codes:

Code	Effect
Press Down, B, A, B, Y, Down, B, A, B, Y during game play	Create box
Press Up, Y(2), X(2), A(2), B(2), Up during game play	Fire energy ball
Press Up, Y(2), B(2), A(2), X(2), Up during game play	Fire rocket projectile
Press Left(4), LB, Right(4), RB during game play	Level select
Press Y, A, B, A, B, Y(2), A, Left, Right during game play	Portal placement anywhere
Press Up, Left, Down, Right, Up, Left, Down, Right, Y(2) during game play	Portalgun ID 0
Press Up, Left, Down, Right, Up, Left, Down, Right, X(2) during game play	Portalgun ID 1
Press Up, Left, Down, Right, Up, Left, Down, Right, A(2) during game play	Portalgun ID 2
Press Up, Left, Down, Right, Up, Left, Down, Right, B(2) during game play	Portalgun ID 3
Press X, B, LB, RB, Left, Right, LB, RB, LT, RT during game play	Upgrade Portalgun