I played this to the end and enjoyed it -- nice job!! It's an impressively expansive map for the time you had, which meant I spent more time with this game. The metroidvania sequencing is nicely done. It had some nice challenges, the heart-drops were nicely tuned, and I thought the checkpoints were well spaced. The look and behavior of the floating flower bubbles was creative and it was something different. My absolute favorite element here was the look of the upgraded sword (the smear frame) -- it was a welcome surprise that made me smile.
In terms of (hopefully helpful) feedback, I think adding invincibility after taking a hit (to avoid having the player get stuck in damage-loops) would be the change that would give you the biggest reward for your time. I know you've heard it, but sometimes it's nice to hear opinions from different players.
It was fun, nice work!