 "Fort Apocalypse" is a multi-directional scrolling shooter where the player navigates an underground prison in a helicopter, destroying or avoiding enemies and rescuing the prisoners.A contemporary of "Choplifter", it has similarities to that game as well as the arcade games "Scramble" and "Super Cobra".Synapse Software's first success was 1981's "Protector", and quickly followed by a number of games written by a small number of programmers.