Every attack in the game from enemy to bosses have been tested to be completely dodgeable. Flat's rain attack is one of the tighter ones to figure out but there are intentional spaces that you can move to and not get hit.
Yeah, I ended up figuring it out after a few tries!! After that, I'm having problems with saving on the Patrick campaign, it always sends me back to the Thermal Tunnels... Anyways, I really enjoyed the whole first campaign, and that final boss was so satisfying to beat, great job here!!