very nice truck, i don't care about hte horizons, because its never a straight flat horizon. i think the best thing to improve these as a group would be to get some consistant editing between them if you can.
I agree that the slightly off horizons is distracting in a few of the pics. It is important to get the scene level, or blow it far enough out of level that it's obvious that was your intent. Otherwise, it's distracting and makes the image look like a mistake.
I like 11 and 12 with a slightly different crop. The editing to the colors does look cool in the shots though. Here's a quick example of what I'm talking about. Since you don't have your "it's ok to edit my images" flag set, let me know if you would like for me to delete this image.