Amazingly epic!
Incredible use of colors and character placement. The way you drew this concept in your own style gives it awesome flair, and it has that look of an old '50s or '60s comic book cover. It's exciting, fun, and appealing to say the least.
The line work is solid and clean, the yellow tint to the color palette works perfectly, and the poster in it's entirety just says everything about Newgrounds successfully. If this poster doesn't speak epic, I don't know what does.
Excellent work, hope it grabs the front page!