I like Jean-Pierre Jeunet a lot, and I hadn't even heard of his latest film MICMACS until I watched it, so maybe my expectations were low. But I think this is one of the most entertaining films I've seen this year. My major criticism of the film is that it is extremely reminiscent of several of his earlier films,most notably AMELIE and DELICATESSEN. Almost to the point that he was making homages to himself.
But other than that, there's a lot to like in this dark comedy about a man who decides to take revenge against two weapons manufacturers who have wronged him. Jeunet has a very stylized look and uses both music and sound design very well. I suppose this is somewhat of an acquired taste since the film received mixed reviews, but though I greatly enjoy his bizarre characters and attention to detail.
I think if you like his previous films, you will probably like this one just as much, but it is quite bizarre.