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.