|Health||Contact with hazards stuns him, falling off treadmill initiates a game over, cannot be killed|
Billy has brown hair, and wears a blue headband around his forehead. He wears a blue shirt, a dark blue belt, and brown shoes.
His weight changes along with the meter in the upper side of the screen. He has five "weights" along the level, which vary from fat to thin, depending of what part of the level the player's in.
Billy is a kid who is obsessed with eating, who can't control himself. When his Uncle Rico finds him overweight and eating, he inspires Billy to get his fat down so Rico can take a photo of Billy and send the photo off to a "contest".
He trains Billy on his highly dangerous Super Treadmill to get his weight down, but every time a level is completed, Billy gets nervous, what makes him hungry, and eats more food, getting extremely fat again.
Eventually, Billy begins to lose interest in using Super Treadmill and entering the "contest", as he's come to accept being fat and would rather eat healthy and exercise if he needs to lose weight. Nonetheless, Rico keeps forcing Billy back on the treadmill due to a vague bet he's involved in.
Billy will start out fat at the beginning of the level, and as the player survives longer on the treadmill, he will slowly get thinner. This will substantially increase his jump height and speed. By the end of the level, Billy will be extremely thin. Billy can move left or right when the appropriate arrow key is pressed. Billy jumps when the up arrow key is pressed.
Billy, unlike most other Nitrome characters, does not have any health. Coming in contact with hazards and enemies will only stun Billy. When stunned, Billy ceases movement and cannot be controlled at all, until he snaps out of him being stunned. A game over is achieved if Billy falls of the treadmill.
- Ice Temple skin - Billy appears running on a treadmill made of ice
- Facebook advertisement - Billy appears as one of the Nitrome characters in the advertisement.
- Billy bears a striking resemblance to the bearded man man from Enemy 585. Both of them wear blue, have brown hair, and have the same coloured shoes. Coincidentally, Super Treadmill was released on Nitrome.com ten days after Enemy 585 was. It is probably just a coincidence, but it is not known if Enemy 585 and Super Treadmill have any connection.
- Billy possibly had binge eating disorder, where someone is addicted to food, and generally eat when are nervous.