Okay while the particles was an interesting idea, you have to remember that you're adding them to a game where the camera is moving in 3D space so you have to move it accordingly. Right now you just add the thing and let it float in the middle of the screen
Also as other people said, add RSMB (ReelSmart Motion Blur), it'll make your videos look far smoother.
My Youtube channel : Mocucha Toribash
RSMB
Here