Major Plot hole: The cunning godly villain Loki sees fit to mind-control a scientist and random SHIELD agents to further his plan but doesn’t think it could also be a good idea to control the director of SHIELD Nick Fury himself – because controlling the leader of the organization you are trying to destroy is simply overrated. Screw you Fury ! I will let my mind-controlled Hawkeye, a man with perfect vision and accuracy shoot you in the chest instead of blowing your head off or at least check if you're wearing body armor like military personnel do , or at least shoot you more than once, or at least look if you're dead or at least try real hard to not suck in the first scene I'm in.
Plot contrivance: Having the technology to become invisible is rather pointless when you are as loud and hot as an erupting volcano. SHIELD’s giant Helicarrier can still be spotted in an instant by radars and thermal vision. Did they seriously think that making their giant flying metal plate invisible would make it harder to spot? Hawkeye and the other henchmen found the Helicarrier like it was nothing: they probably heard the thing from miles away. The genius SHIELD scientist who approved of this costly invisibility project hopefully died in the subsequent military assault from karmic counter-balance.
Plot contrivance: Black Widow has the incredible power of having the least threatening body while using the least threatening guns in Marvel movies: Glocks. She is facing deadly aliens with laser guns BUT somehow never considers that maybe she should drop her stupid Glocks and take the alien arsenal after killing a few soldiers. Fine, she takes one alien gun for a minute and then decides to go back to her flaccid weapons even if there are hundreds of them lying on the ground everywhere. Or for that matter, maybe she could have used Agent Coulson Mega-death gun that seems to be able to harm gods. But no, if there is one Avenger that doesn’t need to be stronger – it’s definitely Black Widow.
Plot contrivance: If Thor had the power to break through the prison’s glass by flying through it, why didn’t he do it before Loki dropped him in the sky? He knew his brother was going to drop him off anyway; there was absolutely no reason for him to not go ahead and destroy that thing.
Plot contrivance: Thor can call the power of lightning to destroy hundreds of aliens in an instant but decides after finding that he is a little too strong that he should fight the aliens with regular hammer strikes because why the hell not right?
Unadressed Issue: As dumb as Thor can be in this movie, he is but a student compared to the mastery of imbecility showcased by the Chitauri aliens. We have an ‘’advanced alien race’’ who has basically shittier war technology than humans and still decides to attack Earth. Sure, they look intimidating with their flying dog-fish rape-child vessels but they have no firepower. The only alien firepower we see in this entire movie are small laser guns from the Chitauri soldiers. And their rotten offensive capabilities are only outmatched by their medieval defense system - aka no defense at all.
Their soldiers have no armor – in fact, Black Widow with her handguns of pure shit is able to mow them down one after the other. And their superior space Mothership has no defense of its own either – taking a nuke in its face with no anti-missile system. And to top it off – when the Mothership is destroyed it apparently sends a signal to all soldiers’ brain to stop functioning because fuck you soldiers. And to top it off even more, if the Avengers had not been there, the U.S. would have launched a nuke on New York city and the shock-wave would have traveled inside the space portal and destroyed the Mothership anyway (since the portal does not close automatically). So....can we say stupid alien race ? Go back on your home planet and breed less stupid war generals and scientists.