"The Overture" certainly had a number of flaws, not least of which was for the audience to figure what was when. I had very little sense of time and place for any of it, and, at first, the flashbacks and flash-forwards were unanticipated and difficult to differentiate from the previous scene.
Nonetheless, such movies provide a rare insight into foreign cultures, and this one did just fine in that regard. The strongest element of "Overture" was the acting. I thought the cast did a generally wonderful job in bringing substance to the disparate collection of characters who populated this story.
While, to be frank, much of the music of southeast Asia is difficult to listen to for extended periods, this film did manage to demonstrate the subtlety and beauty of some Thai music. And is the competitiveness shown in this film part of the reality of traditional Thai music? If so, it seems the Thais have also made music, at some level, into nearly a blood sport.
By the way, some have written here of this film in relation to "Amadeus". To me, it is more like "Drumline".