Tunnel Runner is a game where the player runs through a series of mazes in a 3-D perspective, trying to make it to the exit before one of several Zot Monsters catches them.
Bonus db/cb doorEdit
There are several doors in the game with various functions, but this one adds points to the player's score.
What to doEdit
There is a door with the initials "db" and "cb" on the sides of the door. Once the player runs up to this door, about 1000 points maximum will be added to their score. This will only work when the player first encounters the door, plus turning or looking at the map will cancel the bonus points.
Also, these doors do not start appearing until after the eighth Run.