It is just a demo, but...
...there still seem to be a fair amount of bugs. For example, almost instantly after starting the Flash, it cut to the action screen, and cut off the controls. There may have been a button to see them again, but I didn't see it. I had to restart it many times to see the controls.
The fighting I could see being very fast and fun. There are some delays at times after attacks, which got a bit annoying. I do like the enemy collision though, and the attack sprites look nice.
It is a pretty smooth game, and I look forward to seeing a fully fleshed-out game with this type of fighting engine. It looks to be very fun.