In the Bandito Attack level, go around the course and look for a movie star. Shoot him to unlock Atomic Johnny.
In the Danger Island level, in the jungle area fly by or shoot the snake on the vine to unlock Island Jack.
In the Torpedo Run level, look on the radar. There will be two blips. Go left and shoot the yellow submarine to unlock Professor Guntentaag and Sven 209.
In the Cave Of Blunders level, fly down near the ground. If you see two people; a big man in black who is trying to kill Sheik Abdul. Shoot the killer to unlock Sheik Abdul.
In the Cave Of Blunders level, complete the level perfectly by flying through the left doorway of the castle to unlock the Genie.
In the Thugsville level, fly into the first train tunnel and get the unlock signal to get the Purple Gremelin for race and dogfight mode.
In the Grave Danger level, shoot the tombstone on the left side of the graveyard to unlock Baron Von Slaughter.
In the Monster Isle level, look behind the buildings on the left side to unlock the Rubber-Suited Monster.
In the Monster Isle level, kill the monkey ninja near the roof of bamboo forest shrine to unlock Sammy Wasabi.
In the Coyote Canyon level, in the cave look up at a purple thing. Shoot it and go up. Look for an unlock signal to get the Bandito for race and dogfight mode.
In the Coyote Canyon level, go down to the cowboy town. Look for a girl that is going to be hung. She is Cactus Rose. Shoot her to unlock her.
In Bigfoot Mountain level, go straight at the start. You will see a house. Shoot the snowman to unlock Andre Latoilette.
In the Bombsburg level, fly through the building on the left side of the factory entrance to unlock Marcels Moreso.
In the Bombsburg level, Queen can be unlocked on the right side in a pipe after exiting a tunnel.
The following characters are unlocked by completing all goals and finishing in first place in a race on the corresponding level:
Atomic Andre: Bigfoot Mountain
Marcel Clowns: Bombsburg
Chiquita Bandita: Coyote Canyon
Lt. Island Jack: Danger Island
Human Baron: Grave Danger
Robo-Sammy: Monster Isle
Chicken Sheik: The Cave of Blunders
Sanitation Paulie: Thugsville
Start a file with "ZENBU" as a name to unlock everything in the game.
On the last level in Adventure mode, beat Pilot X by destroying his robot.