hey, thanks a lot for playing the game!
After level one you should buy the "3" upgrade and the "power by 2" upgrade that pushed your character to strength of 9 (3^2). you should then clear the boss in about 13 hits. you can even farm some points and buy the "4" upgrade and get strength 16 and it will be easier.
Still thanks for trying! visuals were made in the very advanced PowerPoint for windows 11.