Well..
Not the best.
But it the graphics were nice.
Try to animate the figure, don't ever ever ever ever ever ever ever ever ever ever ever ever ever ever ever ever ever ever ever ever ever ever ever ever ever use only tweens.
Yea, Krinkels did that too, he got famous, but like this it sucked. No offense.
Try to make more realistic physics.
A skater jumping over a dog and staying in the air for 8 seconds is not realistic.
Also add skater movements:
Let him bend his knees before he jumps, let him bend his knees when he hits the ground again.
And add cool effects and improve current one.
Like sparks coming from his weels or something like that.
You should take a tutorial special effects.
That blood wasn't the best.
But as i said, the graphics were nice, so try to improve one the above things and you'll get a 10/10 5/5 from me.