For your first game, and considering you made it in a very short time, I would say the game is pretty good and there aren’t many things I think you could improve in this situation. Because of that, I’ll separate the feedback into two parts: the first one covers what was possible to do during the game jam’s time span, and the second will be general feedback for games you plan to spend more time on.
Game Jam
The pixel art is pretty good, and the gameplay is heading in the right direction. It was a good idea to show what each item does when the mouse hovers over them, and the description of what happened on the last turn—although simple—was an efficient way to save time and still make the game understandable.
The main issue I have is the total absence of any music or sound effects. I think that if the game had at least sound effects, it would be a lot more enjoyable. I recommend using the site Freesound for sound effects, but for music I suggest you try making it yourselves. (However, I must note that if you don’t have time to compose music, there’s no problem in using Freesound for that as well—just remember to only use sounds tagged as Creative Commons.)
The tutorial has a minor issue: the part where each item is described feels a little redundant, since the player will see a more detailed description during gameplay. Still, adding an in-game tutorial was a great idea that many new devs tend to forget.
Bugs
I found a few bugs while playing. The most impactful one was that all artifacts displayed “number here” instead of the actual number of their effect—this only happened on my first playthrough for some reason.
The second bug is that enemies, when healed by the player’s attack, were able to increase their HP above the maximum HP.
General Feedback
Everything I praised or criticized earlier still applies here, but there are a few extra points I couldn’t mention before because this is your first game and you had a very short development time. So please take the critiques in this section as suggestions for future projects, not direct criticisms of this game.
First of all, I think you could use visual effects to greatly improve the game feel—things like particles and screen shake would make it much more dynamic. You could also add animations to both the player character and the enemies to further improve the experience.
Making the enemies more mechanically distinct from one another would be good too. Even though they looked different and some had more HP than others, it still felt like I was always fighting the same enemy. If you plan to use this idea in future game jams, I recommend giving each enemy a simple, unique mechanic instead of aiming for something overly complex.
Lastly, I just want to wish you good luck in the future—you have potential, and I’m excited to see your next games