In my opinion the panoramic view works very well with a primarily horizontal and “low to the ground” image like this! I wasn’t sure if it was ok to change the aspect ratio of the contest image so I didn’t do it myself, but if it’s acceptable it’ll work well for your piece.
With the added space, I take it you’re planning to put the LC on the left edge of the image? That spot looks just about perfect for it. Perhaps even have the bunker MGs firing at and around the LC - that’d give reason for the primary character’s worried look back at his squadmates Like he was thinking “That could’ve been us.”
There’s just one thing about the character’s head that bothers me, although I really like what you did with his face. For some reason, no matter how many times I look at it, his head seems slightly too small compared to his helmet - or rather the helmet is a little bit too large for his head (as his head looks ok compared to his body and that of the guy in front of him).
It could be just me though?