The Japanese version, Final Mission, was released a year before the American version and there are a few differences between the two. The game's opening story sequence is completely different, showing the obliteration of various cities before the alien invasion begins. Instead of a selectable male or female main character, both players control palette-swapped male soldiers, one of whom is Russian, which was inconceivable for the western market. The game's difficulty was made easier for the American version as well. Instead of six lives, the player begins with only three lives and any upgrade they possess is lost whenever their character is hit. The player's satellites also function differently. Instead of orbiting automatically, they're aligned by the player while moving the character left or right. Their firepower was also weaker. The map shown before each stage in the American version was not featured in the original Japanese version.

The European version, Action in New York, is almost identical to the American version. Besides the title change, the names of the main characters were also changed from Arnold and Sigourney to Silver Man and Sparks respectively. Their respective likeness to their namesakes, actors Arnold Schwarzenegger and Sigourney Weaver, was left unchanged. Their team affiliation was also changed from "SCAT" to "SAT" (Special Attack Team).