Futuremark's Unstoppable Gorg is a refreshing take on the tower defense genre that swaps fixed turrets for rotating orbits, tweaks the typical resource management mechanic, and borrows its aesthetics straight from a 1950s science fiction B-movie.

What will probably grab players first are the game’s stunning production values and campy, overacted cut-scenes that generally feature one of three arch-villains: seductive femme fatale Sereia, solar-powered robot Radiant Beem (pictured above), or the titular leader of the Gorg. There are also plenty of whirling, vintage newspapers that open many of the levels, and if you can read them quickly enough, these give insight into the inspirations and sources (including the Internet Archive) that went into the game's design.

Gameplay tends towards the frantic (especially in the later levels), as players must not only make split decisions on the build order of defenses, but also on which towers to rotate in order to intercept the glowing, serpentine paths of alien invaders. Did you place all of your laser towers on the outer orbit? You might be out of luck when two enemies from a wave slip past. While some might take issue with the trial-and-error approach that some stages require, players will inevitably develop a range of favorite strategies and go-to weapons.

With four difficulty levels, Steam and iOS achievements, a challenge mode that remixes each of the original 21 stages, and a never-ending arcade mode, Unstoppable Gorg offers quite a bit of replay for players won over by the game’s unique visual style. The slinky, theremin-flavored jazz soundtrack also provides a perfect match to the retro-futuristic design.

Currently available for PC and Mac on Steam and as an iPad app (with an XBLA version in the works), this title is a must play for Mystery Science Theater 3000 fans or tower defense enthusiasts seeking a new twist on the genre.

Download the free demo: iPad | Mac | PC