House Robots:
Successfully complete the game in mayhem mode to unlock the House Robots.

101:
Defeat 101 in championship mode.

Behemoth:
Defeat Behemoth in championship mode.

Cassius II:
Defeat Cassius II in championship mode.

Chaos 2:
Defeat Chaos 2 in championship mode.

Hypno-Disc:
Defeat Hypno-Disc in championship mode.

Mortis:
Defeat Mortis in championship mode.

Onslaught:
Defeat Onslaught in championship mode.

Panic Attack:
Defeat Panic Attack in championship mode.

Plunderbird 4:
Defeat Plunderbird 4 in championship mode.

Pussycat:
Defeat Pussycat in championship mode.

Razer:
Defeat Razer in championship mode.

Stinger:
Defeat Stinger in championship mode.

Terrorhurtz:
Defeat Terrorhurtz in championship mode.

Hint: Robot Mayhem mode:
Wait for other Robots to appear so they can fight each other. Push disabled Robots into the pit.

Hint: Easy win:
If you are playing as a Robot with a flipper (such as Behemoth, Chaos 2, Panic Attack), drive in front of the robot. Flip them once, and they will use their Shremec to self-right. Keep flipping them until they go.