Who cares (see my "evolution of a hero" for copywright infringement). I think it's different enough. The hunter is the interesting part anyway. I do know that Threadless have been cracking down on copywright issues recently, but the only way to find out is to submit. If I were you I'd have the hunter shooting one of the ducks and point coming up. Personally I'd like that.
I like the idea and its really funny, but I dont know how well the pixelated ducks go with the vector art hunter. I think the hunter needs to be pixelated to. Maybe just keep the Light Phase gun like it is and make him all pixelated. Also, whats the thing under the top purple duck that looks like an infinity symbol?
the hands look better, but something about the left arm is bugging me. i think, the arm should come below the gun rather than above it. it looks too straight on there.
I'm not sure about the design yet, maybe if I saw a placement of it would be better. I think the hunter should be all the way down and to the left and the birds all the way up and slightly to the right...
I doubt this would pass the threadless legal litmus. I submitted something that had a reworked clockwork orange poster design element (not even the entire poster, just the CO knife/eye bit) and it got rejected for copyright isssues.