Behaviour types
Pick one, then click tiles on the map. Number keys 0–7 also switch type.
Custom slot #7
Give slot 7 a name to use your own behaviour
(e.g. spike, water). Names follow
C-identifier rules (letters / digits / underscore).
Left-click / drag: paint selected type · Right-click: erase (set to none) · Shift-click with Pencil: pick the type under the cursor.
Sprite reactions
For each sprite, pick what happens when it hits
each kind of tile. call_handler means your code
decides (a hook lands in behaviour.c in Phase B).