Tunnel Runner is a game viewed in the first person perspective (the player is never shown onscreen), which requires the player to maneuver their way through a series of mazes, find a key in each one while avoiding its denizens known as Zot Monsters, and escape in order to advance to the next maze (known as "Runs").
- Move (four directions)--joystick
- Check map—button
- Activate Door—up on joystick
- Emergency warp (once per level)--jostle joystick in all directions while pressing button
Once a new game is started, a maze is briefly shown in an overhead view, which is then changed to a first person perspective with the player facing forward. Pressing the button on the controller will bring up the player's map, which shows various objects and maze content, depending on what level the player is on. Originally everything is shown on the map, which includes the maze, Zot Monsters, the player (represented by an arrow), the key and the exit.
The player must travel about the maze, pick up the key, and make their way to either a Single Up or Double Up door in order to escape from the maze and advance to the next one. Being caught by a Zot Monster will result in the player losing a life; once the player is out of lives the game ends.
There is also a timer at the bottom of the screen, represented by a bar; if the player runs out of time before exiting, they will have to go through that level again.
An emergency warp can also be used once per level if the player becomes trapped, which will warp the player to another area of the current Run. A Transport Door also has the same effect.
- Single Up Door—advances to the next level, marked by a single arrow pointing up
- Double Up Door—skips a level, although the player must first locate the Run's Single Up Door and view it before this Door can be activated (marked by two arrows pointing up; double points are also scored upon exiting a Run as a bonus as well)
- Down Door—takes the player back down to the previous Run. No points will be scored during this Run (marked by two arrows pointing down)
- Transport Door—warps the player to a random area of a Run (marked by two arrows on the sides of the Door, pointed inwards)
- db/cb Door—if the player runs across one of these, they will receive a bonus of approximately 1000 points. However, if the player faces another direction or looks at the map before the points are tallied, the bonus will stop. These start appearing on the ninth Run and on
Also, the timeline will freeze whenever the player enters a Door area, which is marked by a shiny area on the floor. The player's momentum will also be halted.
- White—fairly fast and smart
- Grey—slow and stupid
- Red—fast and smart
- Blue—fast but stupid
- The game starts out slow, but then the player's speed increases with the more Runs they clear. Running through levels is not always a good idea though, as the player could run into a Zot Monster by accident and die
- More Zot Monsters are added as the game progresses and they move faster as well
- The walls of some Runs aren't shown on the map, but are replaced with areas being filled in on the map as the player moves through them
- During some Runs, none of the maze walls are shown at all
- The exit disappears
- The key's location disappears
- The player isn't shown during certain Runs on the map
- Certain areas of the game have walls that are pitch black and are impossible to tell what kind of a Door the player is at, since the Doors are marked by one or more black arrows, which can't be seen during these Runs
- One point per room upon initial entry during a Run times the Run number
- Bonus for time left over at the end of a Run
- db/cb Door bonus (varies)
- The Zot Monsters each have a unique musical score that can be heard once they get close to the player.
- Tunnel Runner has two games; game two is the same as game one, although the Runs are random, game one's Runs are fixed.
- The db/cb Door are the initials of the game's designer and his wife at the time, who have since become divorced.
- An additional page to the Tunnel Runner instructions was added after the booklet was printed, due to some changes made to the game, as the Blue Zot Monster was added later and was not mentioned in the instructions originally. (There is still no mention of the db/cb Door though.)
- The key is always initially placed with the Gray Zot Monster.
- The exit is always on the furthest right area of each Run.
- The game will roll over to zero if 1,000,000 points are scored.
- This was one of the two "RAM Plus" games that CBS Electronics released for the Atari 2600 (the other one being Mountain King).
- The game ends/crashes on Run 127.
- The Atari Times review (95%)