Factual error: In the opening sequence just before Minute 1, after the asteroid is reported to have hit Hamburg (Germany), it is shown in red how the mimics spread through Europe. But wrongly this spreading is originating from the center of Europe (somewhere in Austria) rather than in Hamburg (on the far north of Germany). You can even see in the next shot how it spreads from Austria to Germany, Czech Republic, Slovakia and Hungary, which makes no sense if the origin is supposed to be the far north of Germany. (00:00:55)
Factual error: At the beginning, when Cage and the general are looking at the map of the Europe, you can see that they've marked the capital of Croatia as Ljubljana, and not Zagreb.
Factual error: The dam where the Omega is supposed to be hidden first is identified as being located in Germany. In reality, it's the dam at Lai da Curnera in Switzerland. In the German dubbed version, it is correctly identified as being in Switzerland.
Chosen answer: First it should be noted that this film is based on the Japanese novel "All You Need is Kill" by Hiroshi Sakurazaka, which is where the term "mimics" comes from and could be something lost in translation (they adapted to alien planet environments by mimicking the biology of the planet's life, not necessarily making themselves look like a certain species). However, in the film itself it, was said the aliens "mimic our every action", militarily speaking. This is of course because the aliens were resetting the timeline when an alpha died and knew what the military would do, but to the military (and news reporters) it looked like they were just copying our fighting style.
Bishop73