1 - The actors are consistent, and play their role correctly, but one must look at the movie as a teenager movie.
2 - The sound effects and Visual effects are great. Not like transformers but for a movie with 40 Millions of budget its really more than ok.
3 - The scenario is ok but lacks some construction, especially at the end of the movie where the scenarists have taken too many "shortcuts", like [Warning spoiler]: The road to get to the military base is 60 miles, the girl gets there in 2 minutes, finds her brother and gets out, the general leaves the base..and everything explodes.. the last 20% of the movie is like that, at that point I found it..mediocre, which is pitty because it started really great.
4 - The Story construction, is fine and the twist of the [Warning Spoiler] "soldier kids", but again the story takes a dive when we are expecting to see an enemy alien and all we get is the aliens having a human body and pretending they are aliens. I guess the production needed to save money there to at least show us how one alien looks like.
In the end its not a bad movie, if U are a teenager and want to have fun watching a movie with friends, its definetely worth it, if you are an adult who has seen a similar scenario like oblivion with tom cruise, you will probably be disappointed.
Have a great great day