When someone is out, their trail should disappear, giving other players more room

[rjmunro]

As in the original film. See: http://youtu.be/-3ODe9mqoDE?t=45s. As the game is not 3d, the wall lowering could be done by fading the line.

The game could then be run continuously with players joining and leaving, which would work better in a large shared play environment.