Well, I was pretty disappointed by this one and also pretty surprised by the ovation it received in the web sites I've been browsing after viewing the movie, and that's the main reason I react here. This is definitely NOT the outstanding movie that reviewers promise...
Indeed the characters and relationships are funny to watch, and indeed the general self-derisional plot (a movie version of a manga about the misdeeds of the manga itself, plus a bank robbery plot with hostages progressively taking the roles of the robbers themselves) could have been of great interest. But unfortunately something is missing all along the movie.
The excitement of a great robbery plot that takes the viewer in the first thirty minutes of the movie, falls down progressively all along the action slowdowns to finally drawn into inertia. Contrary to what was said elsewhere, even in some of the characters a tenderizing, most are very superficial and they don't really give meaning or bring anything special to the plot...they don't really bring us anywhere nor do they revive the action.
A last positive word though, I kind of liked the ending that really surprised me and specially the words spoken by "Black Cat" : "Life is not like in Anime!", which gives at last a final sense to the action.
To balance my views , maybe that I was induced in error when realizing this was a bank robbery movie (I had no idea what the movie was about until I launched it), and disappointed in realizing that in fact it was a movie talking about social relationships.
So to conclude, not a masterpiece, not a "must see"e, but can be somewhat diverting, specially if you're the average Otaku.