A promising start!
I rather enjoyed this. The animation was good, but the base drawing of things was off in respect to things like proportion and how the soldier types held their guns.
If they did it that way, they'd all have broken ribs. The butts of guns are generally held at the shoulder, not at the collarbone.
The music fit extremely well; metal or orchestra epic would've been out of place.
Plot next time? I certainly hope so. I'm interested by this Jack character.