Controlling the space fighter craft Michael, the player must destroy numerous enemies to stop the Gamma organization from using the alien creature Kassandra to take over the Alpharos star system.

[1] Over Horizon was conceived as a "create your own shoot 'em up" game during a proposal with Pixel to re-use their engine from Dungeon Kid before being reworked into a standard shooter and Hot-B took over development of the project, with Steel Empire co-director Yoshinori Satake at the helm overseeing the process.

The title received positive reception from reviewers; criticism was geared towards its short length and low difficulty, with some regarding it as a clone of Gradius and R-Type but praise was given to the atmospheric and colorful visual presentation, use of environmental stage gimmicks, ability to customize the ship, sound design and gameplay.

Over Horizon is a horizonal-scrolling shooter game similar to Gradius and R-Type, where players control a space fighter craft through six stages, each with their own environmental gimmick and boss that must be defeated to progress further and face Kassandra, a dangerous alien creature that the anti-Federation organization Gamma is using as a superweapon to take rule of Alpharos for themselves.

[11] Sataka wanted to avoid players giving up and improve their skills after dying in the game by introducing the ability to change positioning of satellite pods and weapon experimentation, due to his dislike of difficult shoot 'em up titles such as Gradius II and R-Type.

[4] Hardcore Gaming 101's Michael Plasket regarded it as one of the best 8-bit shoot 'em up titles on the Nintendo Entertainment System, praising the use of environmental hazards, polished gameplay mechanics, graphics and music but lamented the lack of a North American release.