Well... it was sort of lame. Sorry.
The thing is that it isn't very original. The warcraft 3 ending credits have the same cutscene. The terrain was below average, you should avoid blizzard cliffs and add more height/tile/doodad variation. A lot more variation. Blizzard trees are also pretty bad.
The camera was always following the unit from the default w3 perspective which is very bad and boring. Add better camera movement by not making it follow the unit directly and make better angles.
There were also some illogicality. I don't know if you were "serious" or humorous when you created this but generally a human won't evolve into a small zerggling. A dog might, but not a human.
You might also want to add a custom song to match this as it is rather short so importing one song/melody won't do much harm.
You also might try custom models and better effects.
