Thanks for playing! One problem with my game is that I haven't really communicated the "right" way to play it. Others have had the same experience you had, circling around enemies for ages to beat them. Really, most of the levels can be beaten in about 5 seconds.
The high health enemies you faced actually had regeneration, so slowly taking their health is not ideal because they quickly gain it back. To take on these enemies faster, you need to lose health so your sword does more damage. At zero health, you still have a second to survive and you are at your strongest, so I recommend purposefully going down to 0 health so you can deal enough damage to kill the regen enemies. You can also check the video on my page to see how I did it.
If you wanna play the game again, I hope you have more fun with this strategy :)