Steam Hearts

Steam-Heart's is a vertically scrolling shoot 'em up and eroge. There are 8 levels in total, as well as single-player and two-player modes. The primary weapon on the player's ship can either be a vulcan cannon or laser. These shot types can be upgraded or swapped by picking up power-ups.

The player can also choose from a variety of secondary weapons which vary between the versions of Steam-Heart's, but include fixed turrets, flamethrowers, and satellite ships that hunt down enemies among others. The ship can also temporarily boost in any direction to dodge enemies or pick up items. Completing each stage results in a cutscene told through a succession of still images.

The game is set in a world where people have been taken over by a virus, altering their behavior. Two siblings, a male named Blow and a hermaphrodite Falla are immune to the virus and set off to fight it. The characters exchange dialog during gameplay to progress the story. The bosses at the end of each stage are mecha piloted by scantily clad women including catgirls.

After each boss is defeated, Blow and Falla interact with the women. Blow ejaculates into the boss character to cure them from the virus.

Steam-Heart's was developed by Giga and published by TGL. The character designs were done by animator Takahiro Kimura. The game is unusual for combining a shooting game with eroticism, as Japanese erotic games are more typically genres like role playing, adventure, strategy, or even beat 'em ups. It was originally released for the NEC PC-9800 series of personal computers in Japan on March 15, 1994.

The game's first port was on March 22, 1996 for the PC Engine Super CD-ROM² System. For this release, all the graphics were redrawn, the secondary weapons were weakened or removed altogether, and the two-player mode was pulled. It was released near the end of the system's lifespan as its last shooter.

PC Engine Fan praised the quality of the cutscene graphics and character designs in a preview of the PC Engine version. Revival did not find the game to be much of a technical feat, despite coming out towards the end of the system's life. They felt the game was enjoyable but ultimately found it to be a weaker offering than other shooters on the system such as Gate of Thunder (1992).

Reviewing the Saturn version, Ralph Karels in Video Games magazine wrote that the game was standard shooter fare, and was only worthwhile for those that enjoyed the erotic cutscenes. He believed the game could not stand up to the likes of Radiant Silvergun and R-Type Delta (both released in 1998), and found the graphics were not much of an improvement over the PC Engine version. Four reviewers for Famitsu gave the Saturn version a score of 17/40. Three reviewers covered the game in Sega Saturn Magazine (Japan).