FIFE is a cross-platform 2.5D game creation framework written in C++ and Python. Games can be created with a combination of engine, editor tools, game specific scripts, and game content (e.g. maps, graphics, and sounds). The framework is not tied to any type of game (e.g. RTS, RPG), but instead provides a flexible platform for all of them. It supports different isometric views and a pure top-down view. Instead of full 3D flexibility, the engine focuses mainly on using high quality 2D graphics. This puts fewer demands on target platforms and also simplifies the framework and game development.
Java Classic RPG is an RPG framework, engine, and game that uses OpenGL, a challenging AI, huge territories, and classic pen-and-paper turn-based combat. It is in the tradition of games like Wizardry 7 and EOB, but incorporates innovations made possible by modern computing technology. The framework and engine feature a self-containing, playable, algorithmically-generated world, and can be the base for new games.
xBaK is a fan-made remake of the classic Sierra computer RPG "Betrayal at Krondor". It is a game engine that uses the data files that came with the original game by Sierra Online. You must already have your own copy, since the required data files are not distributed with xBaK. The game is still under development. The intro, the option dialogs, and the main game dialog are finished, but the game is not yet playable. Several tools for examining the contents of the data files are also available.
Arx Libertatis is a cross-platform, open source port of Arx Fatalis, a 2002 first-person role-playing game developed by Arkane Studios. Arx Fatalis features crafting, melee and ranged combat, and a unique casting system where the player draws runes in real time to effect the desired spell. The Arx Libertatis source code is based on the publicly released Arx Fatalis sources. This does however not include the game data, so you need to obtain a copy of the original Arx Fatalis or its demo.
The Z-machine Preservation Project is a Java implementation of the Z-machine (Java version >= 5 is required) specification. This Z-code interpreter can be run either as a standalone application or as an applet within a Web browser. It runs Interactive Fiction created by Infocom as well as those compiled with Inform, and targets all existing story file versions. Features include saving the game state, multimedia support (graphics, sound effects, meta data), colored and styled text, undo, and timed input as well as support for different languages. Games in the Inform 7 release format are supported as well (Treaty of Babel specification).