Stylistically, this game is alright, the concept is nice too, but a few nitpicks;
The "Rage Mode" isn't ever mentioned in-game (only in the info for the entry), and even when it happened, the visuals made me think that I was going to have to defend myself, so I pressed nothing initially, only realizing it was my time to attack when time had nearly ran out.
As others have mentioned, not only does the vanilla one have a much more reduced tell compared to the others, the time frame to counter her is almost nonexistent at times; more than a few times I hit the up button nearly instantly on reaction and still got hit.
While you can tell how much life you have left by the effect on the player's body, the heart that appears in the middle of it covers up the numbers, so having that moved to the side a bit so we can see the exact numbers would be nice, too.
Also didn't see any mention in the info or the game itself that rage mode heals you up to full, which is pretty important to let the player know; having some sort of aura around the player after they've healed to let the player know something's happened, as well as an aura around the demon that's about to attack would have been really good to communicate both of those things to the player.
Besides that stuff though, nice work! Would definitely like to see more from you :)