My biggest Problem with ZXC comes from being on a German Keyboard, so Z is in the middle upper row, not neatly next to X/C. Its one of few regular Letters thats not the same on the Layout on 'most' used Keyboards. If you'd bind to keyboard Layout, not actual Letter it'd be better, or to something thats more same-y on 'most' Keyboards.
While i.e. Link doesn't advance, his Sprite looks a lot more active during swinging. And due to how the overlap works on enemy sizes, when you swing you essentially get 2 Tiles of hit with your regular Sword, since you can just hit something with the Tip, and that'd cause the enemy to be knocked back, while in Yancy, it doesn't feel that far, and more like you need to hit with your Swords Center, while also not really increasing enemy to player distance, since i.e. the Scorchwolfes or whatever they were named just keep running into you, even tho you are locked into the Attack animation, so attacking them from the side is basically impossible without getting damaged.
Not letting the Player attack during Invincibility would be fine I guess, I just think currently you don't get enough "protection" against being instantly hit multiple times in a row so to speak. It would also work fine if the knockback just moved the Player/Enemy out of Harms way after an attack. No Knockback on Bosses obviously, that'd look stupid, but if I'm getting stomped by Tantrum, 3 pixels into my backwards direction, which is his center, isn't going to prevent a second hit.
Keep in mind, even how it is I still beat it and didn't ragequit in between, and as said before, am not much of a Fan of the Controls, and am not good at Videogames, so it can't be too bad as it is right now.
I'm not saying Bonesword or something isn't strong, I'm saying a lot feel redundant. I don't need 3+ Swords with range 1 that shoot a projectile straight forward 6 tiles while I have full health, just because one deals 1 projectile 2 hit damage and the other 1/3 respectively. You don't have enough health on Enemies to make that too distinct. Just regular attacks, ranged on full health, boomerang return, always ranged, tile 2 etc. are fine, those are distinct, but once you basically reuse a sword with different Values, you might aswell skip it alltogether.