Entertaining, but not fantastic...
I thought it was fun and certainly well designed, but I agree with Zega000 in that this didn't feel like a game at all, but an interactive story, a story of which I might add isn't that strong and more suited to an all out action over-the-top style of gameplay than a point and click adventure with shooting elements.
I personally didn't find the music much of a problem, I actually thought it was well composed and suited the theme quite well.
The characters are well designed, and each one has their own personality and persona that the player can get into, which is a major plus in any game, even if vinnie seems to be the sterotypical badass and the girl a sterotypical sex symbol with a gun... but that's okay, before this game I never would have considered a stick figure sexy, so I have to give you kudos for giving the internet a new form of sexualality; Stickality
One of the EXTREAMLY needed improvments here is dialogue. Now, before I continue I'm not going to single out this game, but to be honest 95% of the games I've played on newgrounds so far suffer from this same problem, but nevertheless it needs work here as well.
Yes, you have three different characters here that the player can get into, but the dialogue of the characters, and the other people of the world, make scenes so clunky and awkward that it makes the characters feel more like a playable cardboard cut-out for the player to roam around as than an actual character. With one-liners like "Want to eat my dust?" I can see someone seriously needs to go to the dialogue and one-liner school of badassery. Even common phrases like "We are here" could be made more believable with a variation of "We're here". Just imagine an actor saying the line in a movie, say it yourself a couple of times, does it sound right? if not, what do you need to do to MAKE it sound right?
Other than that the other BIG improvment needed is gameplay, there's hardly any of it. The FIRST thing they teach you in game writing is to NEVER make the cutscenes too long and deminish the gameplay. We understand that a story is important, but players who want to play a shooting game want to play a shooting game, not a series of really easy shooting galeries and a crap load of cutscenes with clunky dialogue.
As for gameplay, here's what I suggest you do;
You can take it in two different direction, you can either make it a shooting game with adventure elements, or you can make it a point-and-click adventure elements with shooting elements. Basically, make it a free roaming game like you have here, go to places, collect things, but have big shoot out sequences simalar to the time crisis series of games. An example of this that even share the same character style as this game is here http://www.newgrounds.com/portal/view /25718
That, or you could pattern it after the nostalgic Monkey Island series, where it involves getting information about targets, obtaining items to use and combine with each other to solve puzzels and eviromental obstacles. Like the begining scene where a gun was pressed against Vinnies head, perhaps while play the role of Kiro you have to use an item on something or figure out a puzzle before you can even get to vinnie and save him.
Either way, what you have here is quite an entertaining concept, and as it is kept me entertained for over an hour, it just needs to be dramatically refined and even redesigned to achieve the perfection of sucess that every game designer desires.