After many months I still enjoy to play this! Today I got six gargoyles from the first orb.
I often try to do the challenge to clear everything with 13 hearts remaining. Does somebody have other challenge suggestions?

That's a crazy game! I really enjoyed playing it.
The ghosts work kinda the opposite like blocks in a classic block push game.
You have to think good which formation the ghosts should have since you can't seperate them until one gets buried.
Or if you maneuver them against the edge of the screen, that may change their formation too (I started a second run just to test that).