Only four areas can be reached by normal means with zero flags tripped on your first run (the old country, yellow forest, angry mosquito place, annoying green filter). After fully exploring these areas you have four options for boss fights and no obvious way to bypass them. I tried not attacking the burning lad, using fleeting flame to dodge the fights, using fleeting flame
after the boss encounter trigger removes your invisibility effect, backtracking for quests - no dice.
By contrast, you can explore nearly 2/3rds of Black Souls II at zero flags, so it would be sad to see that small of a roam in a game directly inspired by it. I was particularly sad because at least one enemy
did have unique interactions when I "sequence broke" their encounter.
*Peppering past Bandersnatch isn't a real fog trigger IIRC, at least half of the map is still accessible if you count that as a gate.
Fortunately, I found a use case for a tool I thought was pointless. Several things I have seen shared about the game are highly misleading and imply you can only explore the full map at zero flags with NG+. This is not the case. If you are playing blind or nearly blind and you have a fetish for big beautiful maps (BBM), do not be discouraged. There is a way to pick the lock, and once you do, everything opens up. Think about your options for where to go and where you can't go yet and you'll figure it out sooner or later.
Trivia:
Edit: Fairy forest is gated on both sides and I haven't found a way break into there out-of-sequence yet. Otherwise, I was able to chart a route through everywhere else that appears to be accessible normally.