These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Cliché Storm: A group of Marines, one about to get married, one trying to gain citizenship, one two days from retirement, one with a baby on the way, one a fresh faced rookie, one struggling to cope, and one who lost his brother, use the power of teamwork and More Dakka to defend the United States from an Alien Invasion.
Also, "Marines Don't Quit" from the scene where Nantz tells Lockett that he remembers that The Dead Have Names.
Crowning Moment of Heartwarming: When Nantz decides to go after the drone control center alone, the other Marines come along, despite his orders to stay behind, as well as knowing that it's most likely a suicide mission.
Paranoia Fuel: The aliens can hide anywhere where's enough water, including in your pool.
Sci-Fi Ghetto: Mixed reviews, but the scifi fans seem to enjoy its realistic depiction of how an alien invasion could go. In particular, aspects that have been lauded in other films were less so in this one because it wasn't 'real', such as the faux documentary style that involves Jitter Cam.
The director himself said he didn't want to make a science fiction movie but rather a war movie in which the enemy happens to be aliens.