I tried the game again and I wanted to try dashing and I do do think changing the way you dash could be helpful. Highlighting why the dash is useful would also help. I could avoid most attacks without even trying to dash (which is a good thing) so I barely dashed even though I was making a conscious effort to dash more. Don't take game design advice from strangers, but you could steal an idea from Cup head and have colored bullets that reward you for dashing through them. Maybe give the player a shield or remove the bullets from the screen. I don't know. But the dash as it is feels pretty useless. You could go the opposite direction and cut the dash all together. Replace it with something else or not. Again don't listen to me I am just some jerk on the internet.
I made it all the way to the boss and it was really mean. I found its attacks nearly impossible to dodge and dashing did not help. I am sure with some practice I could beat it, but I didn't try a second time. It should give more of a warning before attacking or have easier to avoid attacks. It felt a little unfair.