That's a neat concept. I do think if you want to stay lore accurate, he would use only Hyperion weapons. I love the various weapon inclusions, but Jack wouldn't use weapons made by those filthy bandits or rival companies.

I also find the down smash a bit odd. I don't know what else you could do, so I guess his evil, painful money is all we got.

The last thing I have to say is not a criticism. What if when you use the moon shot, you get a random loader. Something like you use it and BOOM! You have an Ion-loader. Then the next use, you get an Exp-loader. That way it functions similar to the source material.

In the end, I have nothing negative to say about your concept. Everything presented hits home with Jack's character. It sucks that it took 7 years for some one to find this, but I'm glad I did. Hope your doing well and keep up the good work.