I thought Shannon's performance was chilling, badass, and sympathetic.  I just felt the real Kuklinski wasn't worthy of this portrayal, and I normally don't give a hoot about these kind of things.  Maybe I'm over thinking it, but right now that's my reaction.

I agree, I think the film could've been longer to develop the characters more and give it a chance to be what it might have intended to be.

I thought Shannon's performance was pitch perfect. A portion of one of Kuklinski's interviews was recreated in the film with verbatim dialogue. Shannon's delivery was near identical to the original. He nailed just about every last tick.

Other than that, I thought the film was okay. It didn't seem to give any kind of perspective, new or otherwise, on the subject matter nor explore it all that much. It was more of a documentation of events from Kuklinski's life but mostly just the ones that the media have jumped on the most. Honestly, I think it's a lot more interesting (and disturbing) to watch the real life Kuklinski recall his murders in interviews than it is to see the murders themselves (albeit fictionalized) onscreen.

Not that the film was bad. In many ways, I think is was more or less well done. But there wasn't much to it and I forgot about it quick. Was really looking forward to it too. Bummer.

Agreed, it could have been better.  It was "good," but nothing memorable.