If No Longer Human somehow managed to take Osamu Dazai's furious little novel and make a bloated bore of a movie out of it, Picaresque ends up doing the same thing with Dazai himself. It's a biopic that touches on all the usual beats in the man's life — his literary successes, his turbulent relationships with women, his suicide attempts, his drug habits, etc. — and doesn't manage to do much more with them than subject us to them.
There's some milking of the controversy involving his death (did he jump or was he pushed?), but there's no sense of what would have made him worth hanging out with, or even reading. Get the books instead, especially Self Portraits, where Dazai's cynicism and wit lances out at you from most every page (and where he tells his own story, in "Seascape with Figures in Gold", far more convincingly than you're likely to get it here).