Dunlop found that the large scale of the game necessitated small enemies, which were partly inspired by the characters of "Lemmings". The game's control scheme consisted of a mouse controlling the guns and a keyboard or joystick controlling the mech's movements. Dunlop explained that this allowed the player to maintain freedom of the weapons while simultaneously moving the mech and felt that it "gave the gameplay a bit more depth and interest". In regards to the game's side-scrolling, the team took inspiration from their 1988 game "Menace". When played on advanced Amiga models, "Walker" included a speech between the mech and its headquarters that had been recorded by Dunlop and Glancy over walkie-talkie.