Thanks for taking the time to provide feedback! We're currently reviewing and cleaning up the rulebook, so this helps a ton.
As far as group play goes, the current system would kinda break with multiple people. That said, our original scope was intended for groups - the way dice interact with eachother comes from ideas we had for making co-op dice rolling more fun. Unfortunately, we had to scale things back quite a bit to make the deadline.
We'll be releasing a devlog update alongside a freshly edited, mobile friendly rulebook. Co-op play isn't out of the question, but we'll definitely prioritise polishing the core gameplay first. But hey, stay tuned, we hope to keep updating Incarnation (and other content!) when we can.