Yes. Just use "DarkWave" and "Jump", don't use any other attacks. When the doggo starts using Summon, use the potions under "Items" and to try to keep both of your characters alive - if it's still too hard, a playthrough vid is available on youtube.
While playtesting this, I wanted to make it like those old flash movie games on Newgrounds from 2000, where it was hard enough, so that you'd lose and see the gameover screen at least once, but once you figured out how to beat it, you could see the ending every time - but I probably made it too hard.
Eitherway, thanks for the feedback. :)