Critique: Need Anatomy critique

[Olsie]

Hey there, looking for a constructive critique/ redlining on the anatomy of my two new guys! They don't have names yet but I've paired them up. The arms are bugging me the most and I feel like their poses are kinda stiff? I wonder how I could improve on it, thank you for any feedback

 

[riddles]

so much personality! i think the big glaring thing for me re: arms is the one throwing devil horns to the right. i understand you're trying to convey muscle mass but the way it's drawn makes it look like the actual bone is bent. if that makes sense?