''Gamera vs. Viras'' is the movie where Gamera's love for children became the main plot point. It features stock footage from ''Giant Monster Gamera'', ''Gamera vs. Barugon'', and ''Gamera vs. Gyaos''. Aliens from outer space arrive on Earth and kidnap two young boys, who both put themselves and others in harm's way on more than one occasion by screwing around with an experimental submersible (and trying to have an underwater race with Gamera). The aliens soon learn about Gamera by probing the boys' minds, and much stock footage ensues. The aliens then take control of Gamera and more stock footage ensues. The boys plead with the military to not care about their own lives (in rather noble moment of self-sacrifice) and to destroy the aliens' ship. Gamera is soon freed from his mind control when the boys screw around with the alien ship's controls, and the ship is destroyed after they escape. The surviving aliens then merge into one giant monster, called Viras, who engages Gamera in a duel to the death. Gamera wins after freezing Viras in the atmosphere.
!!This film contains examples fo the following:
* AdultsAreUseless: Yeah...pretty much.
* AlienInvasion: Yep.
* BehemothBattle: The giant flying turtle Gamera fights a giant squid-like creature to protect the Earth from an alien invasion.
* ChekhovsSkill: The two boys' knack for screwing around with device controls and setting them in reverse. It comes in handy later.
* CurbStompBattle: The Aliens' first ship is destroyed by Gamera before it can even approach Earth. The next one learns from it and avoids a direct confrontation with Gamera, instead trying to manipulate him through his affection for children.
* EvilSoundsDeep: The Virasian leader's voice.
* FriendToAllChildren: Gamera is this, and the aliens take advantage of it.
* [[BatmanCanBreatheInSpace Gamera Can Breathe in Space]]: Yep.
* KillItWithFire: Gamera destroys the first Viras spaceship with his flame breath.
* KilledMidSentence: [[spoiler: The first alien during the opening scene, leading into the title card.]]
* [[spoiler:KillItWithIce / LiterallyShatteredLives]]: How Viras is defeated.
* LighterAndSofter: Considerably more lighthearted than the previous films in the series.
* ReCut: There are three, yes THREE different cuts of the film, the only difference being the amount of stock footage.
** Japanese theatrical edition: 72 minutes (available on R2 DVD). Only Gamera's emergence and Eiichi's rescue are shown. Different music track than the other two cuts.
** "Extended" edition (version currently used): 81 minutes. Includes the two ''Barugon'' battles, but only the first ''Gyaos'' battle.
** International edition (version used for foreign releases and the AI-TV version; also released on Japanese laserdisc in the 80s): 90 minutes. The other two ''Gyaos'' fights are included, but are curiously sandwiched between the second ''Barugon'' battle and the first ''Gyaos'' battle.
* StockFootage: So. Very. Much.
* TooDumbToLive: Jim and Masao are smart when it comes to engineering, but they seem to lack, what's it called? Oh yeah, the sense of ''self preservation''.