Here's the list and some thoughts:
Uncle Boonmee (Palme d'Or winner): B (for its poetic imagery and sheer weirdness)
Of Gods and Men (Grand Prix du Jury): A (for its respectful handling of a difficult theme, and for the brilliance of its "Last Supper" scene)
[HOWL]: B (for the way it blends three genres and makes poetry visible)
Poetry (Script prize winner): C (for the last 20 minutes, which however do not redeem the hour and a half before that)
Over Your Cities Grass Will Grow: B+ (art doc on Anselm Kiefer directed by Sophie Fiennes)
[FGAME]: B- (for its well handled script and for the performance of [NWATT])
Rebecca H.: F (can't even begin to explain this one)
Boxing Gym: B+ (great doc by living legend Frederick Wiseman)
Outside the Law: D (for the utterly clichéd way in which everything is handled, and for the most horrible dialogue in recent memory)
Tender Son: B (nice modern take on Frankenstein by Hungarian helmer)
Route Irish: D (for the bulldozing way in which Ken Loach tries to drive his point home)
Ha Ha Ha: B- (because it kept me interested, although this Korean winner of the Director's Fortnight was utterly incomprehensible)
[BIUTI]: B+ (Inarritu delivers the goods even without screenwriter Arriaga, although this is just a tad overly dramatic)
Armadillo: B+ (haunting Danish doc on the war in Afghanistan, filmed right in the middle of the action)
The Housemaid: D (simple Korean thriller, dunno what this was doing in competition)
Two Gates of Sleep: F (for its profetic title)