Work on your particles. After his first step, What is he doing? Your force is good. Your first step didn't connect well to the next move.

I think the step generated energy for the explosion

All in all what you need to do is animating more frames in order to slow your animation down. Yours is way too fast which makes it difficult to see what is happening.
The reason why your movements did not connect to each other is that you almost completely ignored easing and anticipation.
For gaining strength on a really powerful hit you will need lots of frames for the anticipation which go right into the impact without many frames.

referring to the particles I'd say it is a good start, but you also have to slow those down. But make them move in different directions and also not in the same way of movement. but especially take your time, and always animate one particle at once, make it split up in tinier particles, etc. etc.