Great effort
Great effort on this, have a few pointers for you, seeing as you're willing to put time into your work.
The character motivation and staging is flawed in some places. Your characters look alright but there are many areas you could improve on. For example, when the black guy says "don't stand there, we gotta get outta here" The black guy was just standing there. You could have had him turn and run to the door noticing his buddy in shock before yelling to him. Not to mention the fact that there was no initial reaction or dive for cover after that first shot.
As far as staging goes, alot of it was fairly poor. I never understood that the girl was in the vent at first because of how bright it was, you could have darkened her up a lot having rays of light showing through from the vent openings. Not to mention the fact that she got into the vent and had to unscrew the opening... you think it would have been left open as an easy way to pick up the money after everyone ran off. There could have been a better conflict for her, getting stuck like that just made her seem ditzy.
I really like how you showed the drive of the two characters in the initial money trade by having them turn back for the cash, it helped round out their characters more, but the fact that they were meant as side characters yet easily outstaged the main characters was a mistake. Showing them in the initial shot makes the viewers think that they are the main characters in the story while the sniper and the girl in the vent are just supporting cast. Find a way to introduce the main characters and have their actions lead into the conflict. Also, be sure to use action to explain the story rather than speech. If you plan to create more past this, you could have easily left out the "alliance never happens" bit and left us wondering what the sniper's motives were. This would be rounded out and discovered in later episodes resulting in a greater climax and overall appeal to the characters and their situation.
And I just found a random helicopter flying in and stealing the suitcase just plain funny and ridiculous. It seemed like you couldn't think of anything else for these characters to run up against soooo... mmm... random person flies in, steals money, flies away. Even though the sniper can pick off a guy from a skyscraper in a standing position is already trained on their position.
Again, I like the effort you put into the animation and you said this is a first draft of an old comic. Be sure that you stage characters and situations clearly without using dialogue. A great story doesn't always need spoken words. Using it as an aid is alright, but not when it comes to story development. Stopping an alliance isn't nearly as interesting as a sniper getting his gun ready, trained on some stranger on a tower, the iron crosshairs ready to fire, yet remaining quiet. You see two shady people enter the scene knowing all the while this sniper is ready to take SOMEONE out. Why he does it isn't important at this point, who's going to get it becomes all that matters, and then the character development afterwards will do all the explaining.
Good luck on your next work, I hope you take some of the suggestions. Oh and good sound quality too.
(holy crap, long review)