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.
Octaspire Crates! is a scriptable, skinnable, extensible, and relocatable 3D action puzzle game. All the missions, game entities (or crates), game states, and configuration of the game engine are implemented as plain text Lua-scripts. So, if you know Lua, you can write new game entities, game states, missions, and levels with any text editor, without any special development tools. New skins can be created with any image editor that can save .png images, dropped into a new subdirectory under the resources/textures directory, and changed in the configuration file config.lua. Crates has also its own (simple) implementations for all the different container classes it needs (like vector, string, and so on) to keep the external dependencies fewer.