This is a really interesting idea and I think it has quite a bit of potential, but needs some work to really make it shine
Is it clear: The goal is clear, how exactly you achieve it isn't quite as clear. I figured it out, but it took me a while. If I was playing this in a different setting, I don't know that I would've stuck with it long enough to figure it out.
My suggestions in no particular order:
- Add an option to skip or disable the tutorial.
- Make the game round based. I'm thinking along the lines of Brotato. It would help chunk the game up and make it easier to digest. You could also use it as a way to help step the player through the mechanics (e.g., the first level could just require you to stab the sinners and pick up loose souls, the second level could introduce the ability to pickup the sinner, the third level could introduce 1 or 2 eyes, etc.).
- Lower the cap for some of the unlocks, and/or make them progress based on how many of a certain soul you've captured. In it's current form, it feels like it'll take a very long time to get to any single unlock which might turn some players off rather quickly. Allow some early unlocks to make players stronger and encourage them to play more. One way to do this would be giving bonuses every x number of y souls, even if it's a temporary boost... The Behemoth is the only quest that feels reasonable to me at this time.
- Make the keys rebindable, and consider changing the defaults. Since you only have two weapons you only need one button to swap between them, if you plan on adding more the number keys are fine, but there should be a way to cycle through them (e.g., mouse wheel, right click, etc.)
- Limit the type of sinners that can spawn at one time, it's hard to focus on any of the quests when there's 10 different enemy types on the screen at once and the one I want doesn't seem to be showing up. There are a bunch of ways to achieve this, just depends on what works best with your plans for the game.
- I think the Quest U/I could use some work, but that's not my specialty. I did figure it out, and I like that it feels to fit thematically, but it feels messy at first glance.
Also, as I was playing this my wife walked in and said "That's a cool looking game!" She's seen me play a bunch of Game Jam games, and rarely says anything about them, so that seems like a good sign to me.