did you think they showed dd's character correctly in the film ? Is he the type to kill someone who has done wrong to someone else just curious don't know why but i felt iffy on the train scene

I think he has it in him to kill and fights that line more then most heroes do.

He has killed a bit in the past but mainly by mistake. Two that come to mind are he knocked a woman out a window in one of the Frank Miller stories (Man Without Fear mini I think) back when he was first starting out and I seem to remember him trying to save someone that was falling from a roof (a villian I think) but they cut/burned the rope and fell to his(?) death. 
 
Thinking did he not try to kill Mary by kicking her out a window? Seem to remember that being mentioned in a Deadpool story.

I think they were trying to show how desprite the situation was for him which is why he "let him die" and didn't kill him personally. He can choose to save or not, it was mainly for dramatic effect. I liked the movie overall but one thing to consider is that we didn't see the start of the character, so he could have been doing this for a while. Unlike most super hero stories, we see their orgin and begining of the hero.

I was 12 and I thought I knew the character back to front, but then he killed that guy which confused me because that wasn't something I thought DD would do, it kinda ruined the movie for me.

"I think they were trying to show how desprite the situation was for him which is why he "let him die" and didn't kill him personally. He can choose to save or not, it was mainly for dramatic effect. I liked the movie overall but one thing to consider is that we didn't see the start of the character, so he could have been doing this for a while. Unlike most super hero stories, we see their orgin and begining of the hero. "

The movie was horrible. Ben Affleck didnt bring anything to the character. He didnt make it his own. The train scene was just one of the many issues that plagued  this movie.