Shamus is a flip-screen shooter with light action-adventure game elements written by Cathryn Mataga (credited as William Mataga) and published by Synapse Software. The original Atari 8-bit family version was released on disk and tape in 1982. According to Synapse co-founder Ihor Wolosenko, Shamus made the company famous by giving it a reputation for quality. The game was ported to the Apple II, VIC-20, Commodore 64, TRS-80 Color Computer, TI-99/4A, and IBM PC. Several of these were published by Atarisoft. It was later sold on cartridge by Atari Corporation following the launch of the Atari XEGS in 1987. "Funeral March of a Marionette", the theme song from Alfred Hitchcock Presents, plays on the title screen. Shamus was followed by a sequel in 1983, Shamus: Case II, with the same characters but different gameplay. In 1999, Mataga released a remake for the Game Boy Color and later both Shamus and Shamus: Case II for iOS. Gameplay Inspired by the arcade game Berzerk, the objective of the game is to navigate the eponymous robotic detective through a 4-skill level, 128-room maze of electrified walls. The ultimate goal at the end of this journey is "The Shadow's Lair". Shamus differs from Berzerk in having a persistent world instead of rooms that are randomly generated each time they are entered. There are also items to collect: bottles containing extra lives, mystery question marks, and keys which open exits. Opposing the player are a number of robotic adversaries, including spiral drones, robo droids and snap jumpers. Shamus is armed with "Ion SHIVs", SHIV being an acronym for Short High Intensity Vaporizer, and is able to hurl up to two at a time at his enemies. Like many other games in this genre, touching an electrified wall results in instantaneous death. Upon the completion of each level, the gameplay speeds up, increasing the chances of running into a wall. The main gameplay involves clearing the room of all enemies, picking up special items on the way and then leaving through an exit. Upon returning to the room, the enemies are regenerated and returned to their original positions. In exactly the same way as Berzerk, the player will be attacked if they spend too much time in one room. In this case, the Shadow himself emerges from off-screen and hops directly at Shamus, unhindered by the walls. If shot, the Shadow briefly freezes in place. The combination