Arx Libertatis is a cross-platform, open source port of Arx Fatalis, a 2002 first-person role-playing game / dungeon crawler developed by Arkane Studios.
Arx Fatalis features crafting, melee and ranged combat, as well as a unique casting system where the player draws runes in real time to effect the desired spell.
Arx Libertatis 1.1.2 updates and improves Arx Fatalis by supporting modern systems, porting the game to new systems as well as eliminating bugs and limitations. In the future we plan to improve and modernize the engine as well as enable customizations and mods by the community.
Arx Libertatis is based on the publicly released Arx Fatalis sources and available under the GPL 3+ license. This does however not include the game data, so you need to obtain a copy of the original Arx Fatalis or its demo to play Arx Libertatis.
There are packages for Windows, Linux and FreeBSD, but you might also get it to compile and run under Mac OS X and other operating systems.