Having just watched it for the first time, I also could not follow all the characters and their names. But that did not bother me too much. I don't expect to able to follow each word and each plot detail, when I'm watching a movie. As long as I have handle on the general direction of the plot, I'm fine. It's the same way in real life - you don't know everything that happens around you, nor do you get all the words that people utter around you.

Get Carter is one of those films that generously rewards rewatching.
First watch for the emotion and mystery of a tense crime thriller
2nd and 3rd rewatch for piecing together the whole plot, all the players, their actions, motives and consequences.
Subsequent rewatches you finally notice all the small nuances and body language. You finally understand the symbolism and overarching themes. You drink deeply the long lost unique atmosphere/environment of Newcastle nearly 50 years ago.

That'd good to know, because I felt I want paying attention when I clearly was.

A lot of this movie just doesn't make sense. Don't blame yourself.

Yes but the plot turns out to be pretty straightforward and it soon becomes clear.

Agreed.

Yes, I do.
My ratings:
http://www.imdb.com/user/ur0239581/ratings