The "gore," such as it is, is limited to the following:
One character is left lying on a floor, bleeding from facial wounds and half buried in rubble.
Two Mutants (actually, one actor playing two parts in succession) threaten non-Mutant characters. These Mutants have oversized, exposed, and convoluted brains, apparent compound eyes, misshapen mouths, and claw-like pincers for hands and feet. One Mutant is instantly killed and buried under a pile of rubble when a meteoritic bomb strikes and partially levels the building he is in.
The other Mutant is bleeding, and another character says so. This second Mutant gives a character a serious abdominal wound, but the camera understates this. (The wounded man says that his wounds are fatal, but he might be speaking metaphorically or psychologically in that context.) To stop the attack, the leading man strikes the Mutant in his exposed brain with a blunt instrument four times. This causes the Mutant to lose consciousness but does not draw obvious blood or bodily fluids.
This same Mutant chases a woman across a ship's deck, briefly catches her and lifts her off the deck, but then loses his grip and falls, too weak to stand. He then disintegrates into thin air, leaving a thin deposit of apparent ash.
The hero and anti-hero get into a fight on the alien planet. The hero lands two blows, a left uppercut and a right cross, causing the anti-hero to fall unconscious. This character later wakes up, and the hero then threatens him with a rock to warn him not to resume battle. But the two men settle their differences non-violently when pressed by circumstance.
The leading man and lady witness two characters killed outright by directed-energy weapons fire. In addition, a house blows up (shown at a distance), and the leading man later protests the "mass murder" of the people inside it.
The anti-hero twice demonstrates the destructive capacity of the device he uses to communicate at long distances with the hero. These demonstrations produce obvious damage but no physical injury to any character.
The only other violent scenes are obvious allusions to war on an interplanetary scale, and depictions of bombardment and massive urban war damage to a futuristic city. This bombardment and damage continues, and indeed accelerates, during the action. In fact the bombardment rises to a climax as it causes a planet to transform into a star, with obviously fatal implications for anyone remaining alive on that planet. However, on screen, these scenes do not even rise to the level of depictions of artillery or aerial bombardment in typical war films of the period. (And by modern standards, these depictions seem tame.)