Throughout SRB2's development, many versions of the game have been released. Major versions contains a multitude of improvements over the last version, such as changes to the game engine or the addition of new levels. Minor versions usually consist of bug fixes and smaller additions. The below is a list of major versions; information on minor versions is included in the article for the major version they belong to.
- 1 Pre-demo versions
- 2 Demo versions
- 3 Final Demo versions
- 4 Post-demo versions
- 5 External links
These releases of SRB2 precede the first actual demo of the game. They were similar to a tech demo, as they did not include any of the levels intended for the final game and were mainly used to show off the state of the game engine and expand on it.
- Original release date: unreleased, developed March–July 1998
SRB2 TGF was the first version of SRB2. Unlike the current incarnation, it was a 2D game created in The Games Factory, like its predecessor. It was discontinued when SRB2 was moved to the Doom engine in 1998, but many of its level themes and graphics were retained.
- Original release date: October 31st, 1999
SRB2 Halloween was the first SRB2 version made in the Doom engine. It consisted of one Halloween-styled level showcasing basic elements of Sonic gameplay.
- Original release date: December 24th, 1999
The successor to SRB2 Halloween, SRB2 Christmas, included several levels and had a Christmas theme. Five versions were released between late 1999 and early 2000, each progressively expanding on the game's engine to make it more Sonic-styled. Tails was added as a playable character in SRB2 Christmas v0.93.
These demo versions started to add actual SRB2 levels intended for the final game. They also expanded on the engine and introduced netplay, as well as other substantial game elements.
- Original release date: November 2000
Demo 1 was the first version to start work on the Single Player campaign. It contained only one map, an incomplete version of Greenflower Zone Act 1.
- Original release date: March 5th, 2001
Demo 2 introduced Greenflower Zone Act 2, Greenflower Zone Act 3 and Techno Hill Zone Act 1, bringing the total number of levels to four. Knuckles was also added as a playable character, but did not yet have his own sprites.
- Original release date: June 23rd, 2001
- Original release date: December 25th, 2001
Demo 4 introduced unlockable and secret content, such as Special Stages, Castle Eggman Zone, and date-activated secrets such as Christmas mode. Capture the Flag mode was also introduced in this version. In Demo 4.1, Knuckles received a new set of placeholder sprites to replace the ones he had used previously.
- Original release date: March 8th, 2002
Demo 4.35 (originally Demo 4.32) was an update of Demo 4 that ported the game from Doom Legacy v1.30 to v1.32. It also introduced the character select screen, and replaced most of the Special Stages from Demo 4.
- Original release date: March 2003
This was a multiplayer-only demo released exclusively to the Sonic Amateur Games Expo (SAGE) to show off the new multiplayer features of Final Demo 1.01, which was then in development. Among them were weapon rings and the new Chaos gametype. This version also introduced level headers, which allowed mappers to specify settings for their custom maps, such as the name and the background music.
Final Demo versions
This series of releases originated with v1.01, which was intended to be the last demo before the release of the final version of the game, which was to be called v1.1. However, v1.01 was patched several times, and eventually these patches grew in scope and started to add new features, becoming major releases in their own right. This led to a situation where each release was billed as the final demo, only to be superseded by another one. Eventually, this caused the version numbering system to become complicated and inconsistent, as the version numbers were never supposed to reach beyond v1.09.
All of the Final Demo releases included the same lineup of Single Player levels, which consisted of the first two zones and a demo-only version of Castle Eggman Zone. Other levels were developed during this time, but held back for the planned final release.
- Original release date: June 19th, 2003
These versions introduced Techno Hill Zone Act 2 and Techno Hill Zone Act 3 to the game, and added the previously secret Castle Eggman Zone to the end of the main Single Player campaign. Many unlockables were added, including Spring Hill Zone, Mario Koopa Blast and Adventure Example, and emblems were introduced as a method to obtain unlockables.
- Original release date: January 1st, 2004
This version was intended as the next patch after v1.04, but eventually grew to include a number of new features. In this version, the multi-thok was removed, restricting Sonic to just one thok per jump. This version also introduced SOC, a scripting language that allowed users to customize parts of the game that were not customizable before.
- Original release date: September 11th, 2005
These versions fixed several critical bugs in v1.08, and added new editing features to the game. Knuckles's ability to glide multiple times per jump was removed, the Chaos multiplayer gametype was disabled, and Super Sonic received a proper set of sprites. An early beta version of Red Volcano Zone Act 1 was added as a secret level.
- Original release date: August 19th, 2006
These versions added Time Attack and Circuit levels to the game, as well as new editing features and several other additions. v1.09.4 was the last version in the "Final Demo" series and was current for almost three years.
These releases were made after the "Final Demo" approach was abandoned. From this point on, there is no fixed final version and a new major release is made whenever a significant amount of new content is finished. Because of this new approach, releases from this era are substantially more complete and elaborate than before, and should be considered incomplete versions of the full game rather than demos. A new, more consistent version numbering system was introduced for these versions: Releases are numbered as v2.X.x, where X is the major version number and x the minor version number.
- Original release date: February 21st, 2008
This was a semi-private beta version that showcased v2.0's new Match system, much like 2k3 did for Final Demo 1.01. It was released exclusively to the #SRB2Fun IRC channel.
- Original release date: July 24th, 2009
This version introduced nine new stages to the Single Player campaign, increasing the total to 16 levels. The multiplayer gametypes were heavily revamped, adding the new weapon system first showcased in the Match beta and many other gameplay changes. Many new gameplay elements were added in this version, such as new enemies and bosses, waterslides, reverse gravity, and PolyObjects. Many existing editing resources were restructured, and a new palette was added in place of Doom's default palette, meaning that custom content from older versions will need to be converted to work with this and later versions.
- Original release date: March 15th, 2014
This version heavily updated the Single Player campaign, introducing new stages while replacing or significantly changing others. New NiGHTS-themed Special Stages were added to the game, and Time Attack mode was expanded into Record Attack mode. SOC received extensive changes, and Lua was added as a second, more versatile scripting language.
This article gives an overview of plans for future releases of SRB2, including the upcoming v2.2.