Really bad.
There is no plot. Within 10 minutes the "conflict", i.e Billy DaFoe (who is my IRL foe after watching this) gets trapped in an apartment he's trying to rob. Most of the next 85 minutes is comprised of him either trying to escape or scenes of him trying to satisfy his basic human needs. The "climax" is honestly not even worth discussing - it feels entirely unimportant to whatever the "story" is.
There are 3 speaking characters and maybe 15 minutes of dialog total. Sort of like 2001: A Space Odyssey, except that movie was good, and this movie is bad. Really really bad. The 3 speaking characters do not do anything interesting. We only really spend time with Billy, so you might think that he might have some depth, but no. We learn very little about the characters, and the only character change we see over the entire 100 minutes is the protagonist going a little loopy after spending some amount of time isolated in the house.
There are three or four scenes that aren't Billy sucking ice cubes or trying to break windows. They're dream sequences/hallucinations meant to show Billy's descent into madness and pique interest by showing the owner of the house. These scenes might actually verge on interesting, if the movie had developed any sort emotion towards either character by this point in the film.
This film asks no questions and has no answers. It does not pose any problems, it does not challenge anything, It's just boring and bad. Really, really, really bad.