Don't know if it matters but I came across spelling mistakes in some of the notes.
Also the billboards on the lamps intersect walls, they used a normal halo billboard rather than the
no depth test version with the halo activated so it can pass through walls.
Example:
They used the billboard on the left, the one on the right is the
no depth test version and it has the halo option ticked on it allowing it to shine through a wall. The halo option has been ticked for the one on the right so that once the billboard is obscured it doesn't shine through obstacles.