An overall good one...
Graphics: I just love how you've done the units, but you kind of messed up the zerg. I mean, zergling have some kind of, um, "hands", not those ugly spikes, which are specific for the hydralisk, which you messed up again. The 3D models of some specific units from each race, which you see when you choose your campaign should give you enough info for drawing each of them. But, you forgot about the shell of the hydralisk. The zealot was perfect, I like to see you did the 2-knee leg of the zealot. But his blades could be sharper.
Animation: Very smooth, could be faster when the zealot attacks, there was a moment in which the zealot's arm didn't move correctly. I like how you used motion-tweening.
Overall: It's nice, I see you worked alot on this one! Better luck on your next Starcraft tribute!
P.S. This is my first true review of a flash!