I haven't thought about Just Halberds in a very long time. Recently I got questions by email, however. Yay for emails!
After a successful attack, the attacker nominates the next person to go. So, can they nominate themselves again?
I would say: yes, they can pick themselves. It’s a bit like directing where the camera goes next. And in a Conan movie, Conan does all the fighting. It’s up to the other people at the table to call for a change of that’s what they want.
So if the party meets a great archer, can this archer shoot the entire party to bits?
I think they can! I think about it this way: You're a peasant and fighting at tiger or a shark or a soldier. It bites and bites and bites and then you're dead. You didn't stand a chance. What's different with a soldier? Soldiers can be pleaded with. Beg for your life, that kind of thing. And for nightmare monsters, the same is true. Give in to the madness, join the darkness. Talk, beg or grovel your way out of there.
Perhaps my preference is showing, here. I like combat to be short and brutal. The solution to strong monsters being deadly is not to make them less deadly but to offer options outside of combat. Like pleading, offering food, bargaining, promises, curses.
As a referee, you could probably say: initiative is only required if you want to continue the fight. If the giant hits you again and again and again, you can always run away. In my mind, of course, you cannot run away… Or you could lean into the last part: "If you’re down to zero hits, you’re down and out." Player characters aren't dead. They're prisoners, abandoned, naked, imprisoned, whatever ratchets up the tension at the table.
When I ran it, I did not limit spellcasters in any mechanical way. It worked a bit like the newer D&D cantrips. The mage can always use fire bolt just like the fighter can always use their sword. If the spell is more powerful, like the ones marked with a star in the *Example spells from my campaign* section, then those would all need some discussion and that discussion can happen if and when player characters get access to the spell. For some example rulings I would suggest to players:
#RPG #Just Halberds