Not bad, I really like the atmosphere and tension created with the sigils. The beast getting closer and closer from the painting with every wrong sigil is a really nice detail and is very intimidating. I also really like environment and art assets. Also the thing with the mirror at the end was pretty cool. It's cool seeing what the player looks like but it could've been cool if there was some kind of twist like the character is actually a monster or something just generally unexpected. I know putting the mirror there was for the last sigil but it probably could've carried more weight narratively since you can't see yourself up until that point.
There were a few setbacks that could've made the game a lot better. I know many others have said this already but no sound really takes away from the experience. Especially with a horror game where sound is one of the most important parts. I like the game being generally very quiet but if it had little minor sounds for like peeling and stuff and then a scary sound when everything goes dark that would be great.
Also I will agree going back and forth to see the sigils is a bit tedious but I think going back can be a good thing but maybe make it consequential. So if the player needs to go back to view the sigil list they get punished. Maybe make it so the monster gets closer or something else. So it ends up making the player need to try their best to remember which ones they need to get instead of them just constantly checking it. This would add so much more needed tension to the game since if you don't remember the right sigil and the player would get punished for going back, it would make them feel more pressured to take risks which leads to a better gameplay experience.
Also one last thing I'm not sure if it was just me but there was a slight bug with the cursor rendering on top of the game while I was playing and I couldn't disable it. So it was very distracting while playing. Kind of a minor thing but it really bugged me.
But overall this has a ton of potential and was really cool! The horror elements were done really well just missing some things to enhance that and the gameplay could have a bit more consequences to make the tension higher.