I like the art style, especially for the demons lurking underneath the floor boards and the game controls well. Here is some feedback
1. I think it would help the player if you started with some simpler levels, for instance a super straightforward level where the altar and the pentagram are right across from each other. At first when I started playing it wasn't clear to me that this was a sliding block game, so a super easy level will inform THE PLAYER WHAT THE GOAL IS WITHOUT HAVING TO EXPLAIN WITH TUTORIALS OR INSTRUCTIONS. This applies to other mechanics as well, slowly introducing them to the player in simple contexts allows them to learn how your game works so that they will be prepared in more advanced scenarios
2. I think it would be nice if at the beginning of each level The view zooms out to show the location of both the Altar and the pentagram. If it is important to the gameplay that the Altar needs to be discovered, maybe some sort of magical radar could be implemented. another idea is to have the player need to lure or trap a sacrifice in the altar before bringing it to the pentagram
Congratulations on expanding your horizons on building something new!