openttd

OpenTTD recreates and extends the classic Transport Tycoon Deluxe gameplay, letting players build transport networks with trains, buses, trucks, ships, and aircraft across procedurally generated maps. It runs on Linux, macOS, and Windows with SDL/OpenGL backends, and is also distributed via Steam, GOG, and the Microsoft Store. The game requires external graphics and sound data; the project provides free replacements (OpenGFX, OpenSFX, OpenMSX) that can be downloaded automatically on Windows or manually on other platforms. Original TTD assets can also be used if owned. Modding is a core feature: NewGRF files add vehicles, industries, map objects, and game scripts; AI opponents and Game Scripts extend single-player and scenario play. All add-on content can be browsed and installed in-game via the online content service. Social integration plugins (Steam, Discord) are supported. Multiplayer allows cooperative or competitive sessions over LAN or Internet, with dedicated server support. The community maintains a wiki, forums, Discord, IRC, and a translation platform supporting dozens of languages. OpenTTD is licensed under GPL-2.0 with several third-party libraries under permissive licenses (MIT, Zlib, BSD, Boost, Apache-2.0, Unicode). Source builds use CMake; compilation instructions are provided. Savegame compatibility is guaranteed across all versions.