Great movie but I didn't care for how it ended. I thought Josh Brolins character getting killed by the Mexican cartel happened rather randomly ( if anything I was hoping for a final showdown between him and Anton). As for Antons character, going through the movie killing people with an airgun based on the two-face coin treatment was just badass and although i initially hated the lack of backstory of his character, looking back it made the insanity of his drive to complete his mission that much more intense (man of his word, complete mission by any means, without a complete understanding of what made him this way). Lastly I like the last min laugh in the end after the car accident ( "dude that's a freaking bone" )
The decision to do this is precisely why the film is so special.
A final shootout would've been corny and cliched.
What's so great about Brolin's character getting killed out of the blue is it doesn't glamorise it. It shows how matter of fact death is in this world. The whole film is essentially about death/our mortality. Like the old man says at the end "You can't stop what's coming".
This is what elevates No Country over your run of the mill Hollywood thrillers.