Well..
look the animation if GREAT 10 outta 10 for graphics animation and overall visual presentation.
The sound well the music was awesome, the voices were okay. Not great but i cud live with them. But seeing as how the animation was only long enough for 2 sentences to be spoken thats not saying much.
The major problem with this definately wasnt the graphics, or the sound or the voices.
It was the length. This was WAYY too short, i didnt even get a storyline from it it was that short, all i got were a few bombs falling and some dragons kiling people. The only reason i have a faint idea of whats going on is because of the description you wrote.
I know alot of ppl bitch when the backstory of a movie is too long, but its better than no backstory at all, and its not like addint a minute long animated explanation of whats going on wud hurt this animation, it'd atleast make it longer than 40 seconds.
So the only 3 things wrong with this = backstory, voices, length.
Only thing right with it = everything visual.