What are the rules of the game?

Spoilers for season 4.

Now that we know that the whole cycle is a game between the boy and white and the man in yellow, what are the rules?

In lost, one of the rules in the game Jacob was playing with the man in black was that mib couldn’t directly kill certain people who were on a list, which led to him manipulating other humans to kill them instead. This was kind of the only thing that made sense because he’s so powerful he could just kill them whenever he wanted otherwise. Is that going to be the case in from too?

So far we haven’t seen any restrictions on miy, he ripped Jim’s throat out, touched the priest and gave him a heart attack, and made Elgin bleed out of his face. There must be some limitations on his powers or what he is allowed to do but so far he’s been killing with impunity and based on his sack of teeth he’s been doing that for a long time.

So why not just kill Boyd when they’re alone in the police station? Just touch him and make him have a heart attack like the priest?

Why not do the same to Henry and Victor? At this point the behavior is really hard to explain or put any rules to (short of a list of people he can’t hurt which would be exactly like lost), it kind of feels like he’s just doing it for fun?

Meanwhile the boy in white doesn’t really seem to do anything, what kind of game is this where no one knows the rules and the villain is allowed to do whatever he wants?