Runescape (partially found builds of online game; 2001-2012)
RuneScape is a massively multiplayer online role-playing game developed by Jagex Limited, that was originally released on 4 January 2001 as a browser game made in Java. While it can be played for free, players can subscribe to become members, allowing access to far more content. The premise of the game is that players create a character within a fantasy medieval world - they can explore the world, battle monsters or other players, complete quests, or take part in minigames. It grew to become one of the most popular online games, and still enjoys an average player count that exceeds 100,000.
RuneScape has gone through continuous weekly updates throughout its 20 years history, making the current game entirely unrecognisable from the original. Despite these rapid changes, the developers did not make any systemic backups or include any version control until early 2012. As a result, the vast majority of game versions from this time are lost, with practically nothing surviving from 2003-2005.
There may have been many more versions that are unknown. However, only confirmed versions are listed here. These are known either because their version has been recovered, or they were announced in an updated news post at the time, most of which survive.
The game went through numerous different file formats over time.
This search tool will scan a hard drive for all the relevant Runescape files and combine them into a single file that can be uploaded.
RuneScape Classic (2001-2003)
The very early versions of RuneScape from January 2001 to December 2002 would download files to the browser cache, usually "Temporary Internet Files". These files would be downloaded with the extensions .jag or .mem for files containing members-only content. Because they were saved from the browser, a large number of these files have been recovered from various domains in the Wayback Machine.
The most recent copy of each file downloaded would also be stored in the directory C:\WINDOWS\cache-93423-17382-59373-28323.
In December 2002, the format was changed - a "loader" was now downloaded instead, which would install the now-encrypted game files. This had the unfortunate effect that files were no longer saved by the Wayback Machine and would overwrite older versions following each update. From this date onwards, all versions of RuneScape Classic saved their files with names such as g34zx, in the directory C:\WINDOWS\.file_store_32.
RuneScape 2 (2003-2006)
RuneScape's first major overhaul came in 2003, with the development of the "3D update". Substantial changes were made to all graphics, quests, and game mechanics. Due to these changes, the game was known as RuneScape 2, with the previous versions being renamed RuneScape Classic. The beta of RuneScape 2 was launched on 1 December 2003, with the full release on 29 March 2004. The files were still stored in C:\WINDOWS\.file_store_32, but all files had strings of random numbers for names, such as 236861982.
The game's format was altered on 1 June 2004 - as the old format had to redownload all files on a system update, it was replaced with a new format that streamed files directly from the server. They were again still saved in C:\WINDOWS\.file_store_32, but each file had the name main_file_cache.
RuneScape HD (2006-2012)
On 15 May 2006, the game's engine was updated again. Although altered several times over the next few years, this format would remain roughly consistent throughout. There would be many significant changes during this time, such as the launch of RuneScape HD in 2008, a complete revamp of the game's unique combat system in 2012, and the release of RuneScape 3 in 2013. Continual updates and improvements during this time meant the game was very different from how it was in 2006.
While files still had the name main_file_cache, they were moved to the new directory C:\WINDOWS\.file_store_32\runescape. On 29 January 2007, this changed again to C:\WINDOWS\.jagex_cache_32\runescape, before finally being changed again to C:\Users\[USERNAME]\jagexcache in 2011.
Recovery of the lost game versions is currently being tracked in this spreadsheet. 
The search effort is being coordinated in this Discord server.
- Official news posts from 2002 to the present, which announce each time a game update happens. Retrieved 17 January 2022
- Google Spreadsheet tracking the recovery status of known game versions. Retrieved 17 January 2022