Travis Touchdown's appearance and personality was inspired by Jackass star Johnny Knoxville. Suda 51, the game's director, would often show the development team a clip from Jackass: The Movie where Knoxville gets his nipple bitten by a baby alligator in order to show what kind of guy Trevor Touchdown is.
In the Wii version of the game, A Nintendo 64 can be seen on a shelf in Travis' living room. It's best viewed when making Travis check his refrigerator. In the PS3 port of the game, the Nintendo 64 was changed to a Sega Genesis/CD/32X combo, likely due to licensing reasons.
Suda has often said that the cult film, El Topo (1970), was one of the inspirations behind No More Heroes.
Some (but not all) of the T-shirt designs that Travis adorns throughout the game were originally fan submissions to the popular Japanese video game magazine, Famitsu.
The character Letz Shake wears a pair of goggles that look suspiciously similar to the Nintendo Virtual Boy.