Shamus is a flip screen action adventure game written by William Mataga (now Cathryn Mataga) and published by Synapse Software. Originally released for the Atari 8-bit computers in 1982, it was ported to the VIC-20, Commodore 64, TRS-80 Color Computer, TI-99/4A, and IBM PC. Several of these ports were made by Atarisoft. Ihor Wolosenko, co-founder of Synapse, noted that it was Shamus that really put the company on the map by giving it a reputation for quality. It was followed by a sequel, Shamus: Case II, with the same characters but different gameplay.
Mataga's original version was 16K in size and released on disk and tape for the Atari 8-bit family, and later sold by Atari on cartridge following the launch of the Atari XEGS in 1987. The VIC-20 port was 8K and contained only 32 levels (unlike the 128 in every other version). In 1999, Mataga developed a remake for the Game Boy Color, and later, both Shamus and Shamus: Case II for iOS.
Funeral March of a Marionette, the theme song from Alfred Hitchcock Presents, plays on the title screen.