OpenTTD is a clone of the Microprose game "Transport Tycoon Deluxe", a popular game originally written by Chris Sawyer. It attempts to mimic the original game as closely as possible while extending it with new features.

OpenTTD is licensed under the GNU General Public License version 2.0. For more information, see the file ´COPYING´ included with every release and source download of the game.

Significant enhancements from the original game include for example:

• bigger maps (up to 64 times in size)
• an AI that is actually worthy of its name
• stable multiplayer mode for up to 8 players on LAN or Internet
• dedicated server mode and an ingame console for administration
• new pathfinding algorithms that makes vehicles go where you want them to (usually)
• autorail build tool, improved terraforming
• crossing tunnels
• canals, shiplifts
• larger, non-uniform stations and the ability to join them together (of same width or length)
• real checkpoints instead of dummy one-tile stations
• mammoth and multiheaded trains
• much more

Lots of effort has been put into giving OpenTTD a better usability. These include:

• convert rail tool (to rail, monorail, and maglev)
• build stations with drag&drop
• support of drag&drop for almost all tools (demolition, road/rail building/removing, scenario editor...)
• sorting of most lists based on various criteria (vehicle, station, town, industries, etc.)
• mouse wheel can be used to scroll in menus and to zoom in/out.
• autoscroll (to left/right) when the mouse is near the edge of the screen
• build in paused mode
• sell whole train by dragging it to the dynamite trashcan
• cost estimation with the ´shift´ key
• patch options configuration window, change settings from within the game
• "debtmax" faster loan management with CTRL key

Graphical/interface features:

• screenshots can be in BMP, PNG or PCX format (select in game options menu)
• more currencies (including Euro introduction in 2002)
• extra viewports to view more parts of the gamefield at the same time
• window mode with double zoom (CTRL+D to toggle) (MS Windows only)
• resolution and refresh rate selection for fullscreen mode
• colourful newspaper after a certain date
• colour coded vehicle profits
• game speed increase (through fast forward button or by pressing the TAB key)
• snappy and sticky windows that always stay on top and neatly align themselves to other windows
• more hotkeys for even less mouse-clicking

OpenTTD requires the original version of Transport Tycoon Deluxe data files in order to function.