I agree that character development was lacking. I agree that the movie dragged some, especially in the beginning. I also heard more clever lines in Pulp. However, the use of camera, color, location, set up the backdrop of this film with much symbolism, helping to convey this film-noir's aspects.
Once the heist went down, I was along side them, every step of the way. I had to see how it was all going to play out in the end. I wanted to see Stoltz walk away in the end and "get the girl".
You will appreciate this movie for what it is, and forgive it for what it isn't. That is of course, you liked it. I did.