I'm glad you enjoyed the game even with the limited cards/towers/teens we were able to finish! I had the currency/energy name as "spirit power" in mind, but I like the sound of "spook points" :)
Originally, I was planning to require levels to be unlocked in ascending order as you beat them, but I decided for the game jam to let players try whatever levels since there isn't too much content. But yes, if we end up making a full version, I was planning to add more advanced card/tower mechanics and different enemy abilities as the player progresses.
Thank you for playing!