Loved the story, the graphics and the animation.
I had a crash too but could resume after reloading. The crash was at the end of the area where you're heading toward the right and the only gate I remember that looks like the underground walls instead of the brow rust coloured ones slid upward.
I did have one or two mild lockups before that that resolved themselves.
Apart from that my only problem is that the chance of the gun failing to fire even after charging seemed directly proportionate to the proximity of an enemy in front of you T_T
Apart from the bugs, 10 thumbs up :P Love to see what you do next.