On release, reviews praised the game's mix of traditional side-scrolling action and adventure game-inspired puzzles.

Once the password is unlocked in the fifth zone, the computer controlling the invasion shuts down, and the player wins after a final escape.

[8] The game's score was inspired by Jean-Michel Jarre's album Rendez-Vous, which composer Martin Galway had been listening to during development.

[11] Zzap!64 rated the game 93/100 and called it "a neat mix between shoot em up and an arcade adventure, with a few other things thrown in for good measure".

Describing the gameplay, Noel said it initially seems like "just basic components of a fairly good shoot 'em up" but later incorporates elements of adventure games, though stripped of their characterization and complex interactions.

Noel concluded, "Although it's not particularly deep or complex, Parallax and its arcadelike graphics present an entertaining and incredibly challenging puzzle.

[2] The Australian Commodore and Amiga Review, in a 1990 roundup of shoot 'em up games, wrote that Parallax "hasn't mellowed with age and still impresses as much as it did then".

[14] Eurogamer's retrospective review from 2006 rated it 7/10 stars and said that it has "intriguing gameplay variety" and "neat parallax effects", though it is not the most technically advanced Commodore 64 game.