XBS-Bot

Extra points:
Hold Back + Start and press Y, L, X, B, R, A, R, A at the main menu. A sound will confirm correct code entry. You will now have 9,100,000 lift points which unlocks all lifts except for the Moon Gate. You will also have 9,100,000 equipment points, which unlocks all boards, accessories, and special tricks.

All boarders:
Hold Back + Start and press Y, L, X, B, R, A, R, B at the main menu. A sound will confirm correct code entry.

Challenges completed:
Hold Back + Start and press Y, L, X, B, R, A, R, Y at the main menu. A sound will confirm correct code entry. All challenges except for 43 (Race The Chief), 48 (Bomb #5), 49 (Alien Half Pipe), and 50 (Storm HQ) will be completed. You will also have all Bomb Pieces, with the exception of #5.

Alien unlocked:
Hold Back + Start and press Y, L, X, B, R, A, R, X at the main menu. A sound will confirm correct code entry. Challenges 43 (Race The Chief), 48 (Bomb #5), 49 (Alien Half Pipe), and 50 (Storm HQ) will be completed. You will also have Bomb Piece #5.

Shoot projectile:
Hold Back + Start and press Y, X, B, R at the main menu. A sound will confirm correct code entry. Press L + R to shoot a barrel with a projectile.

Slow motion:
Hold Back + Start and press Y, X, B, L at the main menu. A sound will confirm correct code entry. Press L + R when in the air on during a railslide to activate slow motion mode. This mode automatically ends when you reach the ground.

Hint: Faster recovery:
Press A after falling to recover quicker.