Prerelease information refers to information about video games and related media prior to the release candidate. Prerelease information may be gathered from a number of sources including magazines, developer interviews, advertisements and early game footage.
Something similar to prerelease information is unused content. Unused content refers to things found in a game's code that are not used in normal gameplay. Examples may include unused images and models, music, text (usually development or gameplay related) or unused game mechanics. These give insight about the development of the game even if some of the content was not intended to be added to the final game from an earlier date. Densetsu no Starfy 4 and the Japanese version of Super Princess Peach have unused assets that suggest more than one game may have been in development at the same time. Developer notes and build dates are common unused content.
There are a number of different forms of prerelease information.
Conceptual information is information originating before the direction of the game is finalized. It may be found in interviews, or even in the form of unused content in the final game, although in that case it is difficult to verify the date from which the information came from.
In a 2009 conference call set up by Nintendo between Nintendo Life and six developers of The Legendary Starfy, Hitoshi Yamagami suggests that the direction on the game that was finalized as Densetsu no Starfy began as a considerably different project, where Hitoshi Yamagami and Yasuhiro Minamimoto worked on the idea of a "floating character being pushed through [a] maze". Yamagami notes that after six months in the game's development, plans were changed so that players could take control of the floating character instead of pushing it around.
There are two types of conceptual information, alpha and pre-alpha information. Pre-alpha information is from before an early revision of the game is made, while alpha information is information from a revision of a game that is not feature complete. One form of pre-alpha information is concept art.
Concept art is artwork by the game developers depicting how characters, objects and other things should look in the game when it is developed. Early concept art may look significantly different to characters in the final game. Sometimes developers may add concept art to the final game as appears to be the case with Densetsu no Starfy 4's Staff Roll 2.
Information from a workable game
This is information that originated from an early build of the game that is playable to an extent. It is sometimes referred to as 'beta' information, although 'beta' is a misnomer because the game may not be feature complete, as seems to be the case with the Densetsu no Starfy for the Game Boy Color, which did not feature the Extra! option from the List at some point in development. Prototype information may be a more accurate term. 
Unused content from the release candidate
Things found in the final game's code that are not used in normal gameplay. Such information can give an insight into the game's development. It can be difficult to tell when something unused was added to the game's code and it is possible that some unused content was never intended to be seen in the final game, such as Densetsu no Starfy's debug menu.
Inner workings of the game
Through hacking, decompilation, disassembly or trial and error, the inner workings of the game's code can be analyzed and things that were not intended to be found can be seen. This can reveal things such as bugs and glitches that the developers did not rectify, the game's internal name by checking the ROM's header and in cases where it is possible to decompile the game, internal filenames.
Internally, The Legendary Starfy is known as "STAFY5". One example of a glitch in The Legendary Starfy series is the demo glitch from Densetsu no Starfy. The developers did not account for Starfy losing another heart while being caught by the Imadame with no hearts left, causing an underflow glitch and revealing a flaw in the programming.
- Unseen 64, a website focusing on cancelled games, pre-release information and unused content.
- The Cutting Room Floor, a website that documents unused content and regional differences in games, as well as pre-release information.
|Prerelease information and Unused content|
|List of prerelease information||Densetsu no Starfy • Densetsu no Starfy 2 • Densetsu no Starfy 3 • Densetsu no Starfy 4 • The Legendary Starfy (Helpful Stuff)|
|Lists of unused content||Densetsu no Starfy • Densetsu no Starfy 2 • Densetsu no Starfy 3 • Densetsu no Starfy 4 (unused models) • The Legendary Starfy|
|Unreleased games||Unused balloon/bubble pushing games / Densetsu no Starfy (Game Boy/Color) • Densetsu no Starfy / Densetsu no Starfy 2 (Chinese iQue versions)|
|Events and TV shows||Nintendo Space World (2000, 2001) • World Hobby Fair (2002, 2006) • Oha Suta • E3 (2009)|
|Media with relevant information||Game Boy Encyclopedia • Gekkan Nintendo • Nintendo Dream • Nintendo Power • Nintendo Spaceworld Official Guidebooks • Websites|