No spoilers pls; how much of a chore is it to do Route B after A is done.
The game gives you a new way of playing that can be fun and you have a different perspective on some things.
I think mileage may vary, but I liked it.
EDIT:
And I'm not just talking about the main thing that people will probably be thinking about... they actually give you something beyond that that's pretty interesting.
EDIT EDIT:
Like, I didn't try it too much, but you can
hack robots and either put them in your zombie army or use them and fight other robots with a completely new moveset
It's pretty novel.