As the name suggests, this game is a compilation of five emulated Space Harrier games.
It comes with a number of options, such as resolution changes, filters and 2D/3D support for Space Harrier 3D (and the resources for making your own red/blue 3D glasses). Also included are scanned manuals, artwork, sheet music and a demonstration of a professional playing the game.
Of the original Space Harrier, this compilation consist of three versions of it: Arcade, Master System and Game Gear.
It even comes with a Space Harrier themed japanese Sega Master System Boot menu.