Drawn out and boring...
Unfortunately, in this world, one of most eye-catching and exciting devices, the Explosion, has been so over used and copycated that it cease to amaze or excite anyone over the age of 6. This flash was no exception.
The cuts between locations were very choppy, with there being little to no idea where people were at anytime. (For instance, Marco apparently exited out the back of the room, where they had been shooting earlier, into an environment that consisted of a street and a cave?)
Also, none of these guys apparently could hit for the life of them. Though I lost count of how many bullets were fired around 2000 or so, only about 14 people lost their lives. (And for reference, that last sentence was the correct use of the word "their"... check your grammar when typing up a script. You wanted "they're") This situation leads into the unnecessary argument of how long the scenes and dialogue took.
And finally, does everyone need to die in an explosion? With the exception of J.F.K., not everyone explodes when being hit with a bullet.
Still, something good must be said. That is, you did decent with the sprite animation itself.
Try taking some of these tips and return with a shorter, sweeter, less explosive flash.