That was INCREDIBLE!!!
This is definitely your best submission yet! There was a ton of animation, and the movement was extremely smooth! The backgrounds themselves were simple, but they were peretty clear. In addition, the style was AWESOME! The various uses of weapons were clever (as always), and it was cool that you decided to use a moving battlefield (the train)! The music was awesome, too, and the sound effects were very well-done. The violence here was definitely the best I've EVER seen on Newgrounds. The kills were very creative, the blood was very well animated, and it was just plain cool. Finally, there was a decent bit of humor here. Some of the kills were amusing, and the 1337 text was also pretty funny.
This was an awesome submission! The only flaw here was that the backgrounds weren't that interesting, but that was an extremely minor flaw on an awesome flash! Overall: 10/10