Haha ok XD

Unless the sword blade is actually hitting something at the end, the sword arm should continue moving for a bit further, slow down and then stop rather than abruptly stopping like it does right now. Additionally, when he starts to swing his sword, the same thing could be done (where the swing starts slowly due to the weight of the sword but then gradually speeds up). This makes it A) more realistic and B) makes the sword appear to have more weight(since you can't immediately start swinging something really fast if it's heavy, and it's also harder to slow down. You can try this by swinging some heavy object laying around), and thus more power. It would also make the piece slightly more dynamic (it is already, but this would improve it).

Hopefully this helps your future animations!