YaneuraoGameScript 2000 (abbreviated YaneGameScript 2000 or YGS2K) is a scripting and runtime environment for Windows created by Urao Yane (Yaneurao) aimed for the easy creation of game applications. The language is loosely based on C, with numerous game-related embedded functions. It is an interpreted language, allowing one to start coding and/or modifying existing games by simply using text editors like Notepad, without the need to set up file paths or compiler toolchains.
YGS2K is freeware and allows the creation of commercial products without the payment of royalties, however the environment itself is closed source. The author has abandoned the development of YGS2K in favor of his newer game development library, YaneuraoGameSDK. The last publicly available version of YGS2K is 1.64c. Notable features that YGS2K lacks include object-oriented programming, support for Unicode, and cross-platform support.
Heboris, a popular fan game in Japan, was developed using YGS2K. The original author has not updated the program since 2002. However, fans of the game, residing in the 2ch forums, have taken it to their own hands to continue development, bringing it far beyond what the original game was capable of. Despite being obsoleted by its author, and the emergence of ports to compiled languages like C++, Heboris continues to use YGS2K due to its low barrier to entry.
Urao Yane first gained fame for developing BM98, the first Beatmania simulator.
A supporting tool for YaneGameScript exists called YanePack. YanePack allows the developer to pack multiple files into one. Heboris uses YanePackEx, a variant that performs compression when packaging the files.
Most files by Urao Yane are distributed in LZH, a compression format popular in Japan but uncommon in the rest of the world. LZH files can be extracted by WinRAR and several other popular compression software.
Links to both the download pages and files themselves are listed here for the sake of convenience, since the pages are mostly written in Japanese.