You know it sucks but you'll improve at this parts:
•Easing
•Force
•Fluidity
•Anticipation
•Angles
•EFX
Here's some tips:
•Easing
Well as i can see at the animation it lacks of easing
ALOT easing is the part of a animation which means the movement go fast then go slow.In other words force.
•Force
You should charge a lot to create a head removal fist bro O_O,It should have some energy or speed to make it very strong,also add ease at the arm to make it realistic a bit.
•Fluidity
Add some frames to make it fluid,as you can see there's a bunch of animators has a fluid animations,it's because you can see some water like movements that also makes it realistic,You can see a bunch of animations which is Fluid.
•Anticipation
I'll not gonna put some tips 'bout anticipation but i'll teach you what is anticipation.Anticipation is a principles of animation where very needed,anticipation came from the word Anticipate so you should anticipate the movements to make it also realistic
(Sorry if it is all realistic ._.).
•Angles
Honestly the thing you zoom out the animation doesn't called as Angle,it is barely called as camera EFX.
•EFX
The blood efx doesn't looks cool though,find some blood tutorials.
Extra TIP
Where does the guy came?,you should place him at his side because the punch is too near.
Why he doesn't have head?,Add head next time ._.
That's all what i can lol
