He was upset at the Rotten Tomatoes score.
Why is it not serious?
My sister thinks its because he knows hes all alone now (last Kryptonian) while others might believe hes simply sad about taking a life. It may be a combination of things but what is the biggest reason in your mind
He screamed because he lost.
The screaming scene is broad on surface, but can be interpreted in a few ways. Most have mentioned already. One reading I liked is that Clark's scream was a feral response to all the tension he built up, not just from killing Zod, but that he's literally been hearing the screams of thousands of people either injured or dead in a city that had a large part of it destroyed. It's a nice call-back to the "the world's too big, mom" scene. Clark is struggling to contain all the thoughts, not until his mom shows up and tells him to focus on her voice, pretending its an island. Clark does the same thing with Lois at end, focusing on her after killing Zod. She was his metaphorical island in that regard. For all his strength, Clark still needs love and caring warmth to keep him focused.
your theory could have more merit if he was trying hard to close his ears...The screaming scene is broad on surface, but can be interpreted in a few ways. Most have mentioned already. One reading I liked is that Clark's scream was a feral response to all the tension he built up, not just from killing Zod, but that he's literally been hearing the screams of thousands of people either injured or dead in a city that had a large part of it destroyed. It's a nice call-back to the "the world's too big, mom" scene. Clark is struggling to contain all the thoughts, not until his mom shows up and tells him to focus on her voice, pretending its an island. Clark does the same thing with Lois at end, focusing on her after killing Zod. She was his metaphorical island in that regard. For all his strength, Clark still needs love and caring warmth to keep him focused.
your theory could have more merit if he was trying hard to close his ears...
It's because he had to kill, obviously.
Teagone, your explanation is beautiful yet I sincerely doubt Snyder and co really put that much thought into it. I would have loved if they had hinted at that in any regard, but they didn't at all so it sort of falls flat.
He was upset at the Rotten Tomatoes score.