The unmanned sentry guns that can be placed down are inspired by the similar ones in the Special Edition of the movie "Aliens" (1986) according to Scott Johnston, lead designer of Hired Guns.
There was a newer PC version of Hired Guns being developed by Devil’s Thumb Entertainment in Boulder, Colorado, that was announced to come out in 1999 but got cancelled due to Psygnosis leaving the American PC game market in 2000 for PlayStation games.
The Amiga version featured two-stage copy protection. Once the password protection had been removed, the game appeared to be cracked. However, the game woudl recognise that the copy was pirated, and refuse to save the player's progress.