Interesting game, it was actually fun. Looping over the heart and protecting it was kinda fun, honestly.
But here are some key details if you want to make it better:
First, there is no sound in the game except for some enemy sounds. If you had used music, that would have been perfect.
In my playtime, when you die, you just go back to the main menu without any game over screen. It makes things feel a bit weird, as I was playing and suddenly the heart got attacked and I died, but instead of a death screen, it just sent me back to the main menu.
The most essential thing here is the lack of audio. If you add more sounds to it, it would be perfect.
That said, nice implementation of the concept of loop. I personally liked it ╰(*°▽°*)╯