In Microcosm, the player controls a small ship, travelling through the human body to destroy aliens. As an "on-the-rails" shoot-'em-up, the player has control over the ship's horizontal and vertical movements, but movement into the screen along the third axis is dictated by the game. The limitations of the Mega-CD mean a pseudo-3D effect is achieved through full motion video. While some versions of Microcosm opt for a first-person perspective, the Mega-CD uses a third-person view at all times.
The ship has mutliple weapons, alongside a standard shot with limitless ammo. Multiple hits can be taken from enemies before the ship explodes. While it can take roughly 40 minutes to complete the game in one sitting, a password system is also offered.
Unlike other Mega-CD titles, Microcosm chooses to limit its full motion video sequences to 16 colours (a quarter of the 64 available to the system), presumably as a space saving measure.
Microcosm was first seen in demo form for the Amiga CDTV platform in 1991, but soon became an FM Towns title, with development partially funded by Fujitsu prior to the game being ported to other platforms. The full motion video was rendered using Silicon Graphics Indigo workstations alongside life action footage.
Live action footage was recorded at night with an S-VHS recorder, and features members of the team as opposed to paid actors. 2D graphics (and textures) were drawn on Amigas.
In total the game's raw data amassed over 6GB, with image data being stored in 24-bit colour before being compressed for the various platforms. Initial development cost between $600,000 and $750,000 USD.
Microcosm was released for a variety of home platforms, including the 3DO, Amiga CD32, FM Towns and IBM PC. All other versions are able to output higher quality full motion video than the Mega-CD version, and in many cases, at higher resolutions.