Same Old Problem...
Had to turn it off at the halfway mark.
The idea itself is done to death with an added and very annoying flaw - Constant, unwanted, overused, OTT slowmotion.
There is nothing more annoying than people pumping so much heart and effort into sprite-fights only to inject 85% of the movie with continuous aggravating slow-motion.
It could have been fun to watch but, honestly, slowmotion for 5seconds every 2seconds is NOT a good thing at ALL in a fight-scene of any kind, beit movies, flash, gaming or any media.
Please - If you ever remake this, or create a new one, stop with the slow-motion - It's all well and good using it 'occasionally' but 'all the time' is one sure way of making it unwatchable for quite a lot of people.
Check any Sprite Fight from popular authors like the SFvMK Exiles movies, SFvMK series from Proxicide, the SMBZ series or even my own Castlevania Sprite Fight - None of them overuse slowdown and for good reason - It's painful to watch.
Other than that it was smooth and you have a solid foundation to use for future work - However, during the pre-loader, that tune has very annoying crackle and the loop itself is irritating.
Just some basic criticism, don't take it to heart.