You have a few things coming on here that could have been improved before release. For starters, this is nothing more than a cheap test level that would appear in a finished game. This level in particular is not good enough to call a game an alpha or a beta - it is what is called a mockup. If you wanted your game to stand out you would have used original animation instead of pixelated form - and if you didn't want pixelated form you could have actually chosen to gone all pixelated with some intense backgrounds. I admire the shooter concept - who doesn't like a single screen shooter with some bearing as what to shoot at? However, you could have added some kind of innovative gameplay - I, and others do not care what this innovation is - that is up to you to determine; we are the gamers, you are the developer - this is where the difference in burden lies. The music, as much as I like Nyancat, is also redundant when it echos onto another bgm of the same track. You are missing a plot.
You get the idea. Work on your final product before release and then get back to Newgrounds. This could have been much better and really doesn't deserve to be blammed - but your shoddy workmanship really leaves much to be desired.