Fun idea having the opposite side of the dash deal damage. I don't think I've seen that done before. I suspect your control scheme would feel better if the left/right click actually matched the left/right dash direction. My brain doesn't like the mismatch in direction, it feels bad.
Your story bits intrigued me even though this is just about colored squares and blobs. I wanted to know more about what was going on and the fate of this place.
Your enemies probably have too much health for this kind of mechanic. Because you're pushed in the opposite direction of your attack, you have to backtrack a tiny amount to deal damage again. It's not fun and not worth pursuing unless necessary.