There is one screen and the whole board is always inside it. No scrolling, no zooming, no camera at all. That is a deliberate constraint: to solve a puzzle you first have to be able to see it.
Three regions
The screen divides into three from top to bottom.
The top bar is semi-transparent and carries three things: the number of the level you are in, the undo button, and the menu. Being semi-transparent is deliberate — it does not hide the top edge of the diorama.
The diorama takes about three quarters of the screen. The graph of nodes and paths sits on top of the painted scene. All of the level's information is here: threats, lines of sight, items, the exit.
The bottom bar holds your inventory (stone, key, coins) and the button that turns the threat highlight on and off. The hint button lives here too.
In landscape and on wide screens
On the web, or when you turn the phone sideways, the layout changes: the diorama centres and the inventory and controls move to a strip on the right. The information is the same; only where it sits changes.
How a move is made
You tap the node you want to go to. If the node is connected and legal, you walk; if it is not, it is drawn dimmed and the tap does nothing. Which means making an illegal move is not even possible — what is illegal is not tappable in the first place.
Long-pressing a node shows its information: its tags, any item on it, and the toll if it has one.
The threat highlight
With the highlight on, every line of sight is painted on the board, and what gets painted is exactly what the engine computes — not an approximation.
It starts on by default in act 1, because the player is still learning the rules. One tap turns it off, and it can be set permanently from the settings.