I really liked the game.
I think one of the things that frustrated me the most was colliding with my own skeletons (after you build a good set of army defenses it becomes way harder to walk around)
I couldn't play too long so not sure if I missed some spells but I think it would be nice to have some sort of tradeoff to the player
After the daylight you can in theory never move and just stay in place
You're never attacked by the enemies
It would be nice to have some reason to venture away from your "base" and come back (if this happens later in game sorry I missed it)
Overall I liked the game
It took me a couple of tries to get it and become mildly good.
I think it would be good to add a "skip night" button
At the early nights there's not much you can do and you just sit there and wait so skipping forward would be nice
I found the book upgrades a bit chaotic as I didn't realize the text was clicksble but it also took me a minute to understand how it works
I love how it looks and the aesthetics I think a small tutorial somewhere would go a nice way into making the gameplay less hectic
But overall I loved the game
Good job! I hope you optimize it and work on it more post jam!