"Gretchen" is a sweet, funny coming of age movie about Gretchen Finkle the most awkward 17 year old you've ever met. She dresses like she's twelve, hasn't been past second base, and has less than zero self-confidence. She seems to only be attracted to loser guys who treat her terribly, and the movie is about her journey to figure out why that is.
The director walks a fine line between making fun of Gretchen and letting her break your heart, and some people might not get it. I thought the tone was refreshing, and totally different than most "teen" movies (In the end, Gretchen might not become a popular cheerleader or "get the guy", but you still cheer for her all the way.) The actors aren't actually in their teens, however, which is part of what makes it funny. This is a movie made by adults who are looking back on those high school years, and commenting on how over-the-top dramatic everything was. It's funny, and painful.
I watched "Punch Drunk Love" again the other day, and realized that "Gretchen" is much more similar to this movie than to "Napoleon Dynamite" or "Welcome to the Dollhouse" (the two movies that I've seen it often get compared to). Gretchen is like a teenage version of Barry lonely, scared, and harboring a pent-up rage that comes out in totally the wrong ways (Barry smashes a glass door; Gretchen scratches a classmate in the face). But unlike Barry, Gretchen hasn't yet met the person that's going to help her come out of her shell. We're just dropping in on her painful high school period.
"Gretchen" also has a similar tone to "Punch Drunk Love" (the way it skirts the line between comedy and drama), and there is a similarity in the look of both movies (precise compositions, dead-center framing, or the way the camera will rest for a long painful close up of Gretchen's face). Overall, if you enjoyed "Punch Drunk Love", I think you will probably enjoy "Gretchen".