A '''speedrun''' ([[IPA chart for English|IPA]]: {{IPA|/ˈspiːdˌɹʌn/}}) is a play-through (or recording thereof) of a [[computer game|computer-]] or [[video game]] performed with the intent of completing it as quickly as possible, optionally under certain prerequisites, mainly for the purposes of entertainment and competition. The term, a [[Compound (linguistics)|compound]] of the words ''speed'' and ''run'' (as in “running” through a game, referring to the playing of a game) is only used in the context of games that were not originally or primarily designed with fast completion in mind (one generally does not “speedrun” a [[racing game]]; in those cases the game's standard setting for achieving and recording fast times is called a ''[[time attack]]'' or ''[[time trial]]'' mode).<ref name="TimeAttack">Although the term “time attack” is used to indicate a playthough of a game's dedicated mode for achieving fast completions, the term “[[wiktionary:タイムアタック|タイムアタック]]” (''“taimuatakku”'') is the dominant terminology for both unassisted and tool-assisted speedruns in [[Japan]]; the two are not to be confused. There is no commonly used [[loanword]] deriving from the term “speedrun”.</ref> Commonly, speedruns are recorded on either an analog media such as a video tape (predominantly when games on [[Video game console|consoles]] are concerned), or as a digital [[Computer file|file]], by the people (“players”) who make them, for entertainment or verifiability purposes.<ref name="DemoFormat">Despite a large majority of speedruns being released in a compressed video container, such as <tt>[[AVI]]</tt>, and this largely being the preferred format due to the high amount of software that can be used to view them, some communities utilize a game's native demo format (such as the <tt>DEM</tt> format utilized by ''Quake'') due to these inherently being much more compact and thus easy to share with other players. Such demos would require specific software to view, usually (a specific version of) the original game itself. Speedruns produced by such communities that are of general interest to a larger audience are usually also distributed in a more ubiquitous format, such as the ''[[Quake done Quick with a Vengeance]]'' speedrun, which was converted to <tt>AVI</tt> so that people who did not own Quake could also watch it.</ref> Entertainment has traditionally been the reason for the creation of speedruns, as the phenomenon was originally devised by enthusiasts who began comparing each others' playing skills via movies exchanged over the [[Internet]], while verifiability stems from the necessity to provide evidence that one's playthrough went by the typical or game-specific speedrunning rules and thus counts as a valid attempt to beat the record.<ref name="SpeedRunRules">{{Cite web | year = 2007 | url = http://speeddemosarchive.com/rules.html | title = Rules | publisher = Speed Demos Archive | accessmonthday = April 28 | accessyear = 2007}}</ref>
In order to attain the highest possible quality of play in a speedrun, the author usually has to look at and think about the game differently than most casual gamers would. Generally, it is usually required that speedruns are planned out carefully before they are attempted; this need stems from the complexity of the separate areas in which the gameplay takes place. Additionally, games and their physics engines are not flawless and will allow the runner to do unexpected things that could save time. Despite their inherent differences, they seem to share a lot of common traits in this context, such as the ability to disjunct the common sequence of events in a game and thus skip entire parts of it—the act of ''[[sequence breaking]]''—and the ability to use programming errors, or ''[[glitches]]'', to one's advantage.
