Alright, played the game for a bit, here's some of the things I noticed:
The UI is very clean and the sound effects and music are quite satisfying! A suggestion would be to make the X button to close the menus on the top right a little bigger, since it was a bit hard for me to see it at first. Another suggestion is, on the potion menu, could be interesting to not close it automatically after brewing a potion, in the case that someone has materials to make lots of different potions and have to keep reopening the menu for each type of potion they wish to brew.
The tutorial was nice and quick, it taught the mechanics really well! Though, I felt like the first room in the second level was a little unfair, since that melee enemy will just corner you really quickly, forcing you to take damage.
I also really liked the fading effect the flashlight has when it runs out of power.
I'd suggest a small sound effect when you pick up an item, just to give it that little extra feedback that you did pick it up.
I wish the character movement was just a liiiiiittle more precise, since if felt like walking through some of the spike labyrinths was too dangerous due to being a a bit tough to tell if the character would walk where you wanted them to, or if they'd go a little further than expected.
I do think enemy precision and shooting speed could use a little bit of tweaking to give the player more breathing room, especially considering it's the first few levels.
As some others have said, there were moments it was too tough to see, even with the night vision on. A suggestion would be to, when you turn on the night vision, not only do you get the flashlight range you currently do, but also a small circular area around the player that you can see, so they can get a bit more of their surroundings. They currently have that with the flashlight off, but it's a small area and also really dim, so giving that night-vision-small area around the player could help.
I also enjoyed the humor from the pages! Made getting them feel worth it.
Honestly, I wouldn't describe it as janky at all. I didn't really run into any bugs or glitches! I'd say that, with some more variation in the sprite work for the levels, a couple of more gimmicks and different enemies and some tweaks, this game could turn out really nice. Good stuff!