In Stage 3 of Contra: Hard Corps, right before entering the room to fight the Computer Hacker, if the player climbs up the wall, they will find a mysterious character who will ask them if they want to fight in the arena. If the player answers "Yes", they will enter a boss arena where they will fight Simondo Belmont, Psycho Mother, and Warp Bomber. Simondo Belmont appears as a robot carrying what looks to be a guitar case with a sad face sticker on his back. His overall design was based on famous vocalist Masato Shimon, who is known for his contributions to various anime and live action series (a tokusatsu). What appears to be his hair is stylized as a big afro, wears big headphones with antennas, uses rounded sunglasses, and bell-bottomed pants. His right arm can extend into a chain whip, complete with a morning star-like tip, very similar to the Vampire Killer.
At the beginning of the battle, Simondo will come out of a door and destroy a candle, which drops a taiyaki (a fish-shaped cake). He will go and pick it up, somehow looking energized after consuming it.
- Chain Shoot: Simondo will try to get close and hit the player with his chain arm.
- Jumping Chain Shoot: He will jump when the player is on the ceiling (or even randomly) and try to hit the player with his chain arm.
- Taiyaki Throw: He will take out a taiyaki and throw it, which will come back to him. This attack only works on the ground.
- About halfway through the battle, Simondo's head will blow up but he will keep on fighting.
- Simondo Belmont resembles Simon Belmont from the Castlevania series.
- When Simondo throws a taiyaki, it behaves very much like how the Cross is thrown in the Castlevania series.
- Simondo's theme, "SIMON 1994RD", is a remix of the Vampire Killer theme from Castlevania.
- When defeated, taiyakis will shoot out of Simondo's body, making a sound very similar to when the remaining Hearts count takes place after finishing a level in the classic Castlevania games.
- As Simondo blows up, his "guitar case" is revealed to be some sort of bag for hockey sticks.
- Simondo is a parody of Masato Shimon. He recorded the song Oyoge! Taiyaki-kun, which explains why he throws taiyakis.
- The first whip skeletons that appeared in a Konami game (Getsu Fūma Den, 1987) were also originally called "Shimon" (a pun on "Simon", and which translates as "The Gates of Death"), that would explain why:
- ...Simondo uses a whip as his main weapon.
- ...he was inspired in Masato Shimon.
- ...the name "Shimon" was chosen to name the character.