Bug! is a platform game developed by Realtime Associates and published by Sega for the Sega Saturn. It was first released in North America, in 1995, weeks after the Saturn's launch there; in Europe on September 15, 1995; and, in Japan, on December 8 the same year. It was also ported to Windows 3.1x and Windows 95 in 1996 by Beam Software. The game is one of the earliest examples of 3D platforming, as well as one of the first platform games released on the Saturn. Character movement is restricted to a track, unlike many in the genre that allow for unrestricted movement in all directions.

A platformer is a sub-genre of action video games in which the core objective is to move the player character between points in an environment. Platform games are characterized by levels with uneven terrain and suspended platforms of varying height that require jumping and climbing to traverse. Other acrobatic maneuvers may factor into the gameplay, such as swinging from vines or grappling hooks, jumping off walls, gliding through the air, or bouncing from springboards or trampolines.