There have been a few recent science fiction films that have come out that seem to focus on how the characters react to the appearance of an alien life form on Earth. Particularly, one thinks of District 9. Cloverfield, and Skyline as primary examples of this kind of science fiction film making. Monsters is another science fiction film in this vein. The low budgets and no name actors are compensated by the character development and how these characters relate to these nightmarish scenarios of alien life on Earth. In many ways, Monsters may be the best of this grouping in terms of coherent story telling and human interaction.
The premise of Monsters is probably the most plausible due to its simplicity. NASA exploring for life in the universe brings back a sample that unfortunately crashes in Mexico, and in the nursery of Earth, evolves into creating monster life forms. This leads to humanities effort to contain the creatures in some kind of quarantine region. The story of the film revolves around two people, a man and a woman, trying to get back home to the USA by travelling through this quarantined region, and the experiences they encounter.
The film is largely an interaction between the two actors, competently played by Whitney Able and Scoot McNairy, and their reactions to each other whilst they experience the dangers and wonder of the quarantined region. The story in this film is directed and written so well by Gareth Edwards that one does not pay attention to the low budget or the fact that this film is carried by two unknown actors, though I couldn't help constantly thinking during the film that Scoot McNairy reminded me alot of Chris Martin of Coldplay.
One of the best low budget science fiction films I have ever come across.