- Correct Ninjas can't be seen when in terrain. The intention is they don't cross line of sight while moving from terrain to terrain (think jumping from rooftop to rooftop or tree to tree), because they can only kill a guard by being in a lane they still have to expose themselves to danger in order to kill. That may be an interaction to look at for a revised edition.
- Guards can move in whatever direction the Opposition player wants. Picking a facing at the end of the move is meant to let the Opposition block off safe ninja movement paths.
- There can be any number of guards at an intersection, so for ease and clarity, it is best to make the intersections large enough to have guards back to back so they have clear sightlines.
- With terrain, I based it on the assumption of Infinity levels of terrain. Different sized squares works good, and adding some more organic shapes can create more dynamic lanes. I think a good rule of thumb is to fill as much as possible, with three way intersections leaving some blindspots. On my playtest board, there were 22 rectangular terrain pieces, with about ~32 intersections.
Honestly, the board should probably be a bit bigger. Or using smaller scale models, like 15mm or something.