Cosmic Star Heroine is a role-playing game where the player recruits up to 11 playable characters, and chooses a party of four to go into combat with enemies.

There are no random battles; combat takes place on the field like in Chrono Trigger, with visible enemies and bosses.

This acts similar to mechanics in earlier games made by Zeboyd that increase the tension and damage dealt the longer a fight persists.

Araenu has a cyberpunk theme, with megacorporations, slums, clubs and secret bases; Rhomu has a wild-west theme, with saloons, casinos, gunslinging, all underground after war devastated the surface; and Nuluup is a green and verdant planet with mysterious astral powers and a large population of reanimated souls of the dead.

There is a base upgrading system similar to the one from the Suikoden series, in which NPCs can be recruited to join the starship flagship of Alyssa's force.

Alyssa steals the API's flagship and makes it her own mobile base to investigate a spate of recent incidents: dark energy monsters roaming loose, kidnappings, and mysterious attacks.

Alyssa and her party defeat both Arete and the awoken dark god at its alien starship before they can overwhelm the galaxy.

[2] The game was inspired by titles such as Chrono Trigger, Phantasy Star IV, Final Fantasy VII, and Mass Effect among others.

[13] Critics praised the combat system, retro graphics, and the soundtrack, but they found the story rushed, the characters underdeveloped, and the game still containing various unfixed technical issues at launch.

The review noted that the game remained the "most ambitious" work Zeboyd had produced and set itself apart from other indie SNES JRPG tributes.