Nothing new
Lots of submissions these days are using the excuse that the first episode will be completely random and the next will explain it all. Lame excuse for a lack of a decent plot.
As an introduction you didn't bring anything to offer. The first part is always the most important, you need a foundation to keep your audience attentive throughout the whole series.
Your lucky I'm being so generous. 8/10 for you.
For graphics, stick figures are not my thing, I won't rate you on that because its a personal preference. The blood for some reason was bugged when the first person was shot. It stayed on the screen til the next scene. I did like the weapon models I guess. The background was kind of bland though.
Music was annoying all around. Whiney punk rock that just gives headaches. Then again I won't rate you on that since its a personal preference. The sound effects for the guns were nice under all the loud noise you call music.