Its good
10/10 for it so far as you said you cant get the sfx..
Animation is realy good and all so yeah, cant wait to see more, as for the story line..
You said he was a ninja, so i presume he can fight.. if you want to make it become a story then you can have him wake up and run to a dojo to find his master was killed by being slammed into the floor (a small clip will show this in a sort of, flash back) and he seeks revenge on who did, it, I haven't gone into much detail but yeah..
If you need anymore Ideas just message me or something, I could probs come up with more xDD
and cant wait to see more.. you have a fan :)