The aforementioned sandspiel is excellent, along with orb.farm (by the same author), and (shameless plug) my own entry in the genre: https://github.com/JMS55/sa

The aforementioned sandspiel is excellent, along with orb.farm (by the same author), and (shameless plug) my own entry in the genre: https://github.com/JMS55/sandbox https://github.com/JMS55/sandbox