I'm a sucker for melee games and the sword really hits the sweet spot for me. The incrementing damage worked well making the player balance their attacks, waiting longer to deal out stronger combos. Perhaps if you were to increment on this idea, giving the sword more weight or dealing more damage based on how fast the swing was or different damage types if it was a stab vs a swing... who knows, super good mechanic though.
The speed of the player was good for me, dashing felt good too with it's invincibility frames. Boss attacks seemed fair but perhaps lacks the speed like the commentors before me mention. I did appreciate the parts that I felt slow about the player I could upgrade with gold, like the energy metre and stamina.
Well made, visuals are great too :)