As first game jam it was good attempt. if you have just started making games in general, i believe you have done very good job in given timeframe.

however if you would polish this game, you would really feel the different and learn a lot. such as better hitboxes, smoother controls etc. these provide really good game juice to your game and additional personal skill gain and dopamine to achieve those on top of submitting a complete game on your first game jam.
Music was nice.

It was a good attempt...

But the sword swing animation range was too small. I couldn't hit a single slime at all...

I only killed big slimes because I jumped over them when they were attacking...

Also needed a tutorial about what a player should do... (something which I as well didn't do at all...)

Hey, great first attempt at a game jam! It's crazy that you decided to go ahead and join one alone, but the fact that you went through the whole thing and came out the other side with a playable game is commendable in and of itself! 

I have a few tips for your next go in a jam to follow up with. Personally, I feel that the gameplay was a little rough because the swing of the player character was so short, and the monsters we were attacking had such a long range. Through my playthrough, I wasn't actually able to kill or damage any slimes because of how short the sword swing was and a few movement bugs/issues. Beyond that, I also suggest that next time you do a platformer, adding things like signs, coins or other indication items is a great way to ensure that the player knows the intended path to follow. Things like a blind jump off a cliff can be confusing for players who worry they might fall into the void and can also cause misunderstanding about future gaps in platforms so adding something like an arc of rings or even a sign pointed down would solve that issue overall. Finally, I also feel that the UI should never disappear behind objects in the game as that obscures vital information for the player. 

The music was a good pick! I would just adjust the volume next time or include an options menu to allow the player to do so since it kind of blew out my headphones when I tried it for the first time :")

Overall, you utilized the assets at your disposal well and you pushed through to make an interactive and entertaining game for everyone to play. Be proud! You did an awesome job :)

Sick sword swing and animation!

I’d recommend to take a few screenshots and maybe include the basic controls on your game page (which you can still edit, I did the same thing!), because it’s now a bit iffy to download an exe with practically no information at all. I also got transfixed by the attack/defend/dying(?) animations that I wondered why I can’t kill those slimes until I realized you can just jump on them lol

Nice game😎