Average, but still okay.
Well first and foremost, loved the character designs. The cartoony feel to them was great and they really suited their environments. The use of shading was good as was how you drew light onto their hair. The eyes were pretty good as well, and the different head shapes gave ti a bit of variety. However, the Boss's belly was really the wrong shape and looked like it had been rushed. The little tint on his shades was a nice touch.
However, while you put a good amount of effort into the drawings, you didn't animate them enough. Quite often the characters would just stand around and not move at all, which in my opinion ruined an otherwise great flash. You should work on having every character always doing something, even if it's something as little as their chest rising and falling. The gun was another thing that was poorly animated. Instead of having it flick back from recoil every time it was fired, it usually just stayed in the same place. Try to incorporate a bit of reality into the flash next time. Also, there was no flash whenever it was fired and only once did I see a bullet, when the SWAT guy was shot. Don't get lazy when working on things, it really does boost up the quality, and therefore the score.
The backgrounds were well done, but looked a little plain at bits, such as at the very start where it was mostly the wall and floor which had no real distinguishing features other than slightly different colours, but after furniture started appearing it was fixed.
I also thought the sand paper effect at the menu was a nice little touch.
The sound and music was great, as were most of the voices. The only thing that really let it down was when there was a sudden lack of sound (Falling out the window, for example.) If you could try to always have a bit of atmospheric noises, such as police sirens, but not so loud they dominate everything or overrun the voices.
Speaking of voices, Boss's voice was difficult to understand at parts because it was too quiet. Maybe add a subtitles feature so people don't have to turn their volume up? Loved the credits music by the way, but ended far too quickly. You could have played it at the menu too.
Graphically the flash wasn't very violent, which is probably a good thing. The only thing is that a complete lack of noticeable violence made it all a little unreal and not as good as it could have been.
Nice menu, worked fine and had no glitches. Loading time was good and the button worked fine. Next time you could make your own instead of using the newgrounds one as a template, so the play button looked the same as the loading bar.
The humour seemed a little cliche and stereotypical, such as police being obsessed with donuts. Actually, just about every joke seemed to include donuts in one way or another. Maybe spice it up a bit next time so it isn't so bland.
The only other thing wrong with this was that when the Boss called the police, the phone was ringing for far too long and the gaps between each ring was overlong as well.
Overall, this was a brilliant flash, but was dragged down by little mistakes and laziness. Keep your focus, and I'm sure you'll be a brilliant animator! Best of luck to you.