I love this game, it's one of the few games I've given five stars on Kongregate and it really deserves it. It's great. I'm just finishing like my fifth full play-through, at least fifth, and I still love it though I'm currently kind of wishing there was an option to join the Black Robes and be good, betraying them later.
There should be a second where Billy visits one of the other planets of the solar system or the sun. Something along the lines of "Billy the Pilot: 2 Mars".
You should add a zoom or down scope button, at least for the sniper rifles. Otherwise there's little point to using a gun that can't fire fast, can't zoom and doesn't have a large clip.
Controls are a little too floaty and Vandheer Lorde on hard is way HARD. Those are probably the only complaints I have for it, great game, really good combat mechanics(would love to see more moves or combos), the atmosphere and setting and subtle coloring was just GORGEOUS and I really liked that. The controls and the overwhelmingly unfair fight in hard mode against Vandheer Lorde are the only turnoffs. All in all, a favorite.
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 "Billy the Pilot"){kind=icon}
 "High Tea"){kind=icon}
 "Dead Zed"){kind=icon}
 "Culmination"){kind=icon}