Source Releases are a means by Piga Software to release unfinished source code drafts to the public for comment and review. Unlike many free software projects, Piga does not adhere strictly to the principles of open-source software development, feeling it inoperable for artistic oriented software such as computer games. Hence the Source Release model allows a means of incorporating elements from open source development within a more traditional cloistered approach, with Source Releases not intended for widespread attention beyond the developer and testing communities. As such, they are not to be promoted to the same extent as a final stable release. Alexei: Part XIII however was done as a "preview release" to reflect that the engine is not likely to be changed that much later on, unlike say Lamp Refugee, and instead adding more game content is the main priority of later releases.