While the lineart and colouring work really well, I find the pose and the background to be a little lacking. I can’t really speak to the latter, as I don’t really do backgrounds often, but as for the former, I find the Predator’s punch to be pretty stiff. It looks like he isn’t really putting anything into it, and that the impact would be pretty weak. Try and have him put his whole body into it; have him really lean into it, have him bend his knees to stabilize himself. I’d recommend looking up some references online, using an action figure to model the pose you want, or, if all else fails, do the pose yourself or have a friend do it for you.
For Mando, on the other hand, he looks very out of the fight. His pose is very open, and something I’d imagine would look a lot better in a scene where he’s looking out into the distance. Mando’s a very defensive fighter, often drawing his arms into his body to close himself off and defend himself with his gauntlets. I’d recommend trying something like that. Also, if you’d like to keep the spear, you could always have him hold it in front of him with both hands, like he’s trying to block the attack with the spear.
I hope this helps
Thanks, I agree for the most part. I think the reason it looks so stiff is actually BECAUSE I relied too heavily on action figure reference. I appreciate the feedback!
No problem! What type of action figures were you using?
One of them was straight up the black series mando figure. The Predator was an infinity war captain america.
Ah, I see. I’m not super well versed in traditional action figures, but I’ve found black series figures don’t have all the articulation I need. I find the GI Joe classified series to be pretty amazing, particularly Destro, so maybe those might be better?
Thanks, I’ll look into those!
No problem! Glad I could help!
I think it was Stuart Sayger who described Bionicle as “Possibly the most posable action figure on the planet” so there’s always that to consider. 
I am now aware of the irony of my statement. The only thing is Bionicles tend to have wacky proportions, and they are horrible for anatomy references.
If that’s your issue try wooden mannequins. They are made with the express purpose of being used as drawing references so they are top choices in both poseability and proportions.
Ehn, I don’t like those. I find they lack some pretty basic possibility. You’d be better off with those art reference figures you can find on Wish; the ones that are kinda like Figmas