Bridge Builder

Bridge Builder is a series of computer games developed and published by Chronic Logic. Bridge Builder is the first in the series, followed by Pontifex, Pontifex 2 (later renamed to Bridge Construction Set ), and Bridge It. The object of each game is to construct a bridge which a train may cross over, given a limited budget and available materials. Bridge Builder, which is no longer supported, is freeware and entirely two-dimensional, while its sequels use all three dimensions, but are considered demoware; the full version must be purchased from Chronic Logic's online store.

Gameplay
Each level is composed of a section of land, such as a river or chasm, and an initially laid track that shows the train's starting and ending points. A number of anchor points in and around the chasm are where the player anchors the bridge from. Should the player's train cross the bridge successfully and under budget, the level is passed. Later games add additional constraints such as a boat that must pass underneath between two consecutive train crossings.

Although Bridge Builder only allows the player steel beams, bridges in later installments can be created using a variety of materials. Along with varying strengths of steel, the player can also use cable or hydraulics that expand or contract for some purpose, such as to allow a ship to pass underneath the bridge. In all games, the player is constrained by a budget that determines the maximum amount of material that can be used and still pass the level.

There is no penalty for failing a level; the player may try and test infinitely many different designs before finding one that succeeds. A poorly-designed bridge may break as soon as the player begins to test it, unable to support its own weight. While testing the bridge, the stress on each section can be seen, representing both tensile stress and compressive stress. If the stress becomes too great, that section breaks and disintegrates, possibly jeopardizing the entire structure.

Reception and Legacy
Pontifex 2 won the Independent Games Festival Audience Award in 2003. In praise of the original Bridge Builder's flexibility, 1UP.com stated "the sheer variety of solutions provide more entertainment than expected and Bridge Builder quickly becomes less of a game and more of a toy." Peter Stock, creator of Armadillo Run, cited Bridge Builder as an inspiration for his game. Chronic Logic also sponsors multiple contests to see who can build the best bridge. World of Goo's first episode features a level called Ode to the Bridge Builder.

In 2006 creator Alex Austin released an updated version of Bridge Builder, known as Bridge Building Game, adding more levels and options.

Add-ons
Bridge Builder comes with fifteen levels, though over a hundred fan-made levels are available for downloading. Contests sponsored by Chronic Logic are held every few months, with the winner(s) receiving a free Chronic Logic game.