The paint scheme is great! Very dark and foreboding like a Deathjack should be. The pose looks OK to me, though he would benefit from a different position for his fingers and chains. The only other thing I would have like to see a bit more pronounced (personally) is the green Cryx glow...it's one of the things I like most about Cryx and I think it would also give some life (or is that unlife....) to this model. Very nice subtle weathering on the model as well.
LOVE the base, the pose is okay, see the paint job is nice but the pose of the arms lose's the epic evil bulk of this model so idk maybe just try a diff pose, but all n all id love to face off against your cryx! and i love the weathered chiped area's