Realism to an extreme: a movie as slow as life (Lake Tahoe)

The 2006 Mexican film "Lake Tahoe" is a completely honest film in the "dogma" style: shot in near real time (takes places over course of one day, with real-time sequences broken by black screen visual ellipses) with no special effects, no soundtrack, mostly amateur actors probably, real settings in what appears to be a small city in the Yucatan. If you watch it for plot (or for that matter for images of Lake Tahoe, which you'll never get) you're on the wrong track: plot is super-simple (spoilers here, though not much to spoil): teenage boy drives his old car into a post and spends much of the morning trying to guy a part to get the car started again, in the course of which he meets a young guy who will befriend him and a young woman with whom he'll have a brief fling; boy is very distracted and withdrawn, and we gradually learn that his father has died perhaps the day before - he goes home a few times - his home is quite a bit more upscale than the other places he visits during the course of the movie - where his mother is drowning her sorrows and his kid brother is left more or less unattended. That's pretty much it; nothing truly happens, and there's no resolution. I admire the movie for fulfilling its intentions, but have to say I found the pace soporific; I don't need an action film or any complex plot design to draw me into a movie, but this one was so austere and glacial that it almost defies the audience. Also, would have been a stronger movie if it had less ambiguity: I know things are never wrapped up in real life as they are in a 90-minute commercial film, but still I was left scratching my head: how did the dad die? why are there no funeral arrangements or crowds of family and friends at the house of the mother (even if she's not still with the father? that was unclear)? Why such a distinction in social class between the boy with the car and everyone he meets or visits? Where was he heading at the outset and why? And what's the significance of the title (whose only reference in the movie was a bumper sticker on the car from Tahoe, which kid brother pastes into his scrap book)? Mystery and ambiguity are certainly welcome elements in films, but in this one the mysteries are huge black holes in the middle of an already extremely spare movie - director and writer have some obligation, I think, to fill in at least some of the blanks.