* FamilyUnfriendlyAesop: Even {{lampshaded}}.
-->'''Gribble:''' I was a good kid. Followed orders, put my toys away. That's why they took her, because of me. What kind of message is that to send to a little kid?
* InferredHolocaust: Oh, sure Milo [[spoiler:saved his mother and got home]] but there's the small issue of the evil fascist regime that's been in power on Mars for decades. During which time they've been casually throwing [[spoiler:baby males]] into the garbage to fend for themselves, training the females to be unquestioning enforcers, executing dissenters and [[spoiler:murdering countless human women]]. All apparently carried out by Martian society at the whim of one individual's insanity. The past evil deeds and problems facing Mars are unlikely to be instantly solved by revealing society was [[spoiler:built on a lie.]] Somewhat averted in that they have Gribble and Milo [[spoiler:(and his mom)]] to guide them through the internet connection.
* {{Narm}}: After Milo wakes up his mother moments before being vaporized and she has a moment to realize what's going on, she lets out the whiniest, most awkward scream of terror imaginable.
* NightmareFuel: See [[NightmareFuel/MarsNeedsMoms here.]]
* TheScrappy: In a movie full of Scrappies, [[ManChild Gribble]] is probably the character audiences hated the most.
** Milo himself deserves a mention for being an UnintentionallyUnsympathetic SpoiledBrat who was highly inconsiderate and unreasonable at the beginning of the film.
* UncannyValley: As [[http://www.youtube.com/watch?v=_aS5W___Ezk this trailer]] demonstrates, the movie easily surpassed ''WesternAnimation/ThePolarExpress'' in terms of creepiness. It doesn't help that they used an actual kid for the voice but based the motion capture off of Creator/SethGreen, hence the dissonance. And the baby Martians, oh man, ''those baby martians''.
* UnfortunateImplications: A [[http://www.somethingawful.com/d/current-movie-reviews/battle-los-angeles.php?page=2 Something Awful review points out]] just how strictly this movie adheres to conservative family roles: the Martian women have assumed positions of power that have left them completely unable to care for Martian children ([[SarcasmMode as there's no way someone can hold a full-time, influential job and be a loving mother at the same time]]), the Martian men have become effete layabouts as a result. The movie concludes that Martian children will only truly thrive when raised by a mommy and daddy, and anything other than the traditional nuclear family isn't capable of raising children.
** Not helped by the fact that Milo only describes his mom as doing domestic things, like vacuuming, doing laundry and taking care of him.
* UnintentionallyUnsympathetic: Milo's EstablishingCharacterMoment of spitefully refusing to do his chores doesn't exactly do much to endear his character to the audience. That the rest of the intro has him continuing to be disobedient towards his obviously overworked mother doesn't help matters. It is obvious that they're supposed to be signs of missing his absent father, but the fact that he takes it out on his mother combined with him not really receiving any relatable character traits, and the fact that he just seems a bit too old to be throwing such tantrums just makes him look like a huge {{jerkass}}.
* WhatDoYouMeanItsForKids:
** The hype makes it sounds like a comedy, but [[spoiler:the kidnapped mothers get their brains drained before being vaporized. No wonder Gribble didn't want to tell Milo the truth behind why he's on Mars.]]
** [[spoiler:Milo's mom almost gets vaporized to provide memories for the new generation of Nanny-Bots, then Milo gets shot in the foot with a laser and suffers not from excessive blood loss from GETTING SHOT, but will now die because his helmet broke, and then his mom pulls a HeroicSacrifice to save him, dooming her. This also spawns some FridgeBrilliance.]]
* TheWoobie: Gribble is this. To recap, he wasn't a naughty boy. He was a good lad, listened to his mom, did everything he was told to do. As it turns out [[spoiler: that's why the Martians took her from Earth. Like Milo, he followed the Martians in an attempt to rescue his mother. Unlike Milo, he failed to save his mother.]] This left him alone on Mars. He's had no social contact with other humans for at least 20 years and has had to live with the burden of knowing that [[spoiler: ''he'' is the reason his mom is gone]]. Is it any wonder he doesn't act like a normal human being? Chances are that he acts so comically in an attempt to mask the pain he feels.
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