Just found this game... love the game design, art, music, sfx... every aspect of it, really. I see it has been on a slow burn for a few years... any plans for more updates or a Steam release?
Couple of suggestions that might help for late game FPS issues:
Skulls and hearts are always active. They *could* activate on demand like eyes and colons do. Skulls could launch individual bones only when there is a mob near enough to that bone's path that there is some chance of a collision.
Collected soul orbs could be consolidated into larger orbs that represent multiple souls, eg. a large orb representing 8 souls, a larger orb for 64, and a huge one for 512. Not to suggest they clock over like normal base 8 numbers... 15 souls would be 15 orbs on screen, but 16 would be one large and 8 small.
Couple of QoL suggestions:
When placing teeth I usually want to place several of them. Teeth could be a special case that does not require clicking on the gravestone for each new tooth, placement mode could stay active until player right clicks the ground or left clicks another gravestone.
I think the heart pulse gfx would work better underneath other gfx.
edit: Was reading some other comments about a sandbox mode... it would be nice if beating the queen for the first time unlocked an option to start the game at wave 10 so you have all parts unlocked and about 50 souls to spend. The introductory levels are a lot to wait through once you are familiar with the game.