* {{Anvilicious}}: The Second Part is extremely left wing oriented, showing a group of young [[LaResistance gaucho-type futuristic cave dwellers]] fighting a despotic dictatorship of aliens with Juan Salvo as a Che Guevara-like [[FollowTheLeader charismatic leader]]. This doesn't apply for the original first work.
* FirstInstallmentWins: This work has a few controversial editions:
** El Eternauta, Remake: (1969) By Oesterheld and Breccia. A leftist pamphlet with several [[TheyChangedItNowItSucks drastic changes to the storyline]], which coupled with Breccia's [[QuirkyWork weird and experimentalist approach]] arose an uproar from the fans. Consequently, it [[ExecutiveMeddling got rushed up]]. It's not merely that the alien invaders are depicted as TheEmpire, [[EagleLand a certain somebody even helps them and all!]]
** El Eternauta, Third Part: (1983) By Ongaro, Morhain and Oswal. Just your [[SoOkayItsAverage average]] sci-fi comic, reusing the characters in some uninspired setting and considered by many to have been made mostly [[CashCowFranchise to cash in]].
* MoralEventHorizon: Despite fighting an extermination war, the protagonists never torture or execute any enemy. As a matter of fact, being common and decent people, they always are plenty of moral concerns regarding their doings, and never think selfishly, even in the most dire situations.
** However, in the DarkerAndEdgier sequel, Salvo makes a FaceHeelTurn, making his disregard to human life somewhat of a shock for the fans of the first part (and even for his comrades in-story).
*** Possible FridgeLogic explanation: those years of deep space wandering really [[CharacterDevelopment took their toll on Salvo]], who used to be a nice and caring family man. The guy is out for revenge.
* TheyChangedItNowItSucks: While the original series is widely regarded as Made Of Awesome and even taught in schools in Argentina, the Second Part in comparison is considered inferior by many hardcore fans. The same thing is true for the 2000's in-universe sequels made by Solano López and Pablo Maiztegui, though it was a serious product and sold fairly well, itself a miracle given the Argentine economics.
* WhatDoYouMeanItsForKids: The series was aimed for kids and teenagers when it was first released. Kids and teenagers... of the 1950s. Not modern kids. Nowadays, an AlienInvasion seems like a good escapist fiction, but not this one. It starts with a disaster that kills everybody but a few survivors, those survivors violently turn against each other, many characters die in gruesome ways, familiar places of Buenos Aires are destroyed in extricated detail, circumstances are bleak and only get even more bleaker, every HopeSpot is crushed... and no, there is no HappyEnding at the end. [[YouCantFightFate Quite the opposite]]. And if you thought that superhero fiction prepared you for aliens, laser, mind control, super-strength and the like, guess again. And if there is a moment of levity here or there, it's just to make the later disasters even harsher.