Retro Gamer listed it as number 6 on their list of "The 20 Greatest PlayStation Games You've Never Played". GamesTM described it as a cross between Parodius, and Coryoon. In 2014, Eurogamer listed the game among gaming's "most valuable treasures", praising the graphics, humor, and noting that while not difficult, it has personality.
Multiple reviewers noted the similarities between Harmful Park, and the Parodius series and described the game as a "cute em up". Upon release, Famitsu gave it a score of 26 out of 40. The game was released in Japan on Februand re-released in 2012 for the PlayStation Network again only in Japan. The developer intended the game to have comedic elements, and to be enjoyable for a wide variety of gamers of all ages and both genders. Harmful Park was developed by Japanese game developer Sky Think System, and it was the final game they developed. The park has now been converted into a fortified base. Another scientist orders her daughters to reclaim the park, using flying machines. Tequila makes the rides and machines of the park go berserk. The game is set in a theme park, after a scientist named Dr.
Three additional minigames are available as well. "Pie spread" for example fires continuously, while "Jelly Boomerang" tracks enemies, but has low attack power. There are four kinds of shots that the player's ship can fire, each with their own strengths and weaknesses. The game also features exotic weapons, including jelly beans and ice cream.
Enemies in the game include gorillas, inflatable dinosaurs, and a gigantic woman. Roller coasters play an important role as the main. Each building can be customized for its appearance, prices and also the length of the ride. It is a theme park management game where players build their own theme park with roller coasters, rides and food stalls. Harmful Park is a horizontal scrolling 2D shooting game. Sim Theme Park is the sequel to Theme Park and the second game in the series.