Obviously this is still in development, and I feel like there's not enough here to really evaluate the game you're trying to make--you have this intriguing-sounding backstory in the description, but what we see in the game is a princess fighting slimes, and I'm not able to really gauge how they will connect. (It's also got quite a few bugs.) It's an interesting idea though, so I'd be interested in seeing it when it's more fleshed out.

You need to tell the player what the controls are, especially if the attack button is just some random key rather than one of the first keys you would guess e.g. space, LMB etc

Nice game! I thought the pixel art was cool and gave the game an old school feel. I think the combat mechanics can definitely be polished and tweaked, but it's a good start! (I did run into a bug I should mention - the door opening sounds were repeating constantly throughout the game until I reached the boss level.)

I also would have liked to see a bit more of the story hinted in the game's description. What is described there sounds really great, so I would have liked to learn a bit more (maybe through a scene or two of dialogue before throwing the player into the action). Nice work though, and congrats on submitting to the jam!