The acting is quite good even if it is a bit over the top at times and caricaturish at others.
My biggest problem was with the score. I don't think it worked on any level. It didn't feel like it fit at all. While there are elements of comedy in the film, the score seemed to think it was playing while a circus was on screen or clowns were performing or something. It was just too whimsical for me and really detracted from the film imo.
Junkie plays better than any trailer could ever show. It's a tad serious, a tad kooky, a tad unique, and yet a little too familiar. It's not for everybody but I found myself enjoying it well enough considering it's not very funny, not filled with action, isn't exactly gory, not quite a horror flick, and not the drug induced funfest of say a film like Trainspotting. But I still liked it! :)