This is a underrated masterpiece from director Adam Green. All of the actors give great performances; you can actually feel the characters' terror when they realize the severity of their predicament. In particular I liked Shawn Ashmore's performance in this because he played a similar role in another survival horror film The Ruins (2008); unlike that film, however, his character in Frozen has a lot more development and characterization, and the chemistry between the characters in general is miles ahead. I really hope Green can make more collaborations with the actors in the future - maybe that Killer Pizza film adaptation?