Alright so i decided to reinstall Deus Ex after not finishing it and I had a question. I remember at the end of the first mission i killed only a few people and my brother was not really pleased with it. Then i tried it again and managed to kill no one and he praised me for it. 
 
So my question is will how i play alter the ending I get? If i just go through the game guns blazing will I get a bad ending or does it just depend on the dialogue choices i make?

No, you can get any ending regardless of how you play.
 
Some key plot points might change though.

How you play the game has no bearing on what the ending's like. It only changes 1 line of dialogue Adam says.

How you play the game has no bearing on what the ending's like. It only changes 1 line of dialogue Adam says.

@Xolare said:

How you play the game has no bearing on what the ending's like. It only changes 1 line of dialogue Adam says.

This is the Deus Ex forum, not DE: Human Revolution :P