* AdaptationFirst: "New World Order" was demoed in the ''Countdown to Extinction'' sessions in 1991, but given to a band called Zoetrope, whose version came out in 1993. Megadeth have since released 3 versions of it, the 1991 demo (released as B-side to "A Tout le Monde" in 1994), a studio recording (released on ''Duke Nukem: Music to Score By'' in 1998) and a remake (released on ''Thirteen'' in 2011).
* ChartDisplacement: "Symphony of Destruction" might've been their sole Hot 100 hit, but it did rather poorly on Mainstream Rock. Their best-performing hits are "Trust" (#5), which the band still plays live, and the two lead singles from ''Risk'', an album both the band and the fans prefer to forget.
* ContractualObligationProject: The band agreed to make a GreatestHitsAlbum to finish off their deal with Capitol Records, showing some WriterRevolt for it in its title ''Capitol Punishment: The Megadeth Years''. Ditto later compilation ''Still, Alive... and Well?'' to finish off their deal with Sanctuary Records.
* CreativeDifferences: What killed the classic line-up after ''Risk''. Marty Friedman was less and less interested in metal, and was far more interested in pop music, moving to Japan and doing J-Pop almost immediately after leaving the band, while Dave Mustaine languished in creating the more commercial music he grew to intensely dislike.
* CreatorBacklash:
** Dave says he doesn't like ''Risk'' too much, but he still thinks it's a good pop album.
** The band as a whole hated the improvised, low-budget cover Combat Records created for ''Killing Is My Business...''. The 2002 remix/remaster's cover art was a much more faithful rendition of the sketch Dave made and the label had lost two decades prior, as was the rendition on the 2018 remix/remaster.
* CutSong: Dave's original plan was to cover the Sex Pistols song "Problems" on ''So Far So Good So What'', but then-guitarist Jeff Young suggested that "Anarchy In The UK" would be a better choice, and the label felt so too. As a result, they recorded both, with "Anarchy" making the album and "Problems" eventually coming out as the sole exclusive on the ''Hidden Treasures'' compilation in 1994. The ''Warchest'' box set includes a session take of the two songs played one after the other.
* DoingItForTheArt:
** Gar Samuelson and Chris Poland weren't metalheads in the least, and Poland has gone on record saying he only did Megadeth because the music was equal in complexity to the jazz fusion he loved playing. Post-Megadeth he ended up going back to jazz fusion, despite it not really being a commercially or financially successful genre.
** Marty Friedman's whole approach. He joined Megadeth because he loved metal, then left and started doing Japanese music when he felt he'd outgrown metal, money be damned.
* ExecutiveMeddling:
** Bud Prager. Responsible along with Mustaine for making ''Risk''.
** The cover of "These Boots" on ''Killing Is My Business...'' was removed from pressings of the original master released after 1995 after Lee Hazlewood, the song's original writer, threatened legal action. For the remaster, Megadeth was allowed to use "These Boots"...but they couldn't use the Megadeth version. Thus, they recorded it with the original lyrics, and then {{Sound Effect Bleep}}ed all the lyrics that were changed in the original cover. Dave wasn't happy about any of this, and made that very clear in the liner notes and in his autobiography. Fortunately, the original version is quite widely available [[KeepCirculatingTheTapes amongst fans]].
** Mustaine had originally intended ''The System Has Failed'' to be his solo debut; however, it was branded a Megadeth album because he owed Sanctuary Records one more studio album. [[note]]A compilation album, ''Still, Alive... and Well?'', was released a couple of years prior in an attempt to fulfill contractual obligations.[[/note]]
* FanCommunityNickname: [[Literature/AClockworkOrange Droogies.]]
* FollowTheLeader: ''Many'' parallels with Music/{{Metallica}}'s career. Most of the bands' albums had similarities in the execution, with Megadeth usually following Metallica's lead. (''...And Justice For All'' and ''Rust In Peace''; ''Metallica'' (The Black Album) and ''Countdown to Extinction''; even ''Load''/''Re Load'' and ''Cryptic Writings'', to an extent.) Inverted after ''St. Anger''; Metallica's ''Death Magnetic'' is a comeback in the vein of ''The System Has Failed'' (though some will say that said comeback also happened around the same time with ''Endgame'').
* HeAlsoDid: Marty Friedman started his career in Cacophony, a neoclassical metal project also starring Jason Becker.
* KeepCirculatingTheTapes:
** The Capitol Records era albums have all been reissued with the much derided [[GeorgeLucasAlteredVersion 2004 Remixed & Remastered releases]], leaving the original mixes out of print and sometimes hard to get, though ''Peace Sells'', ''Rust In Peace'', ''Countdown to Extinction'' and ''Youthanasia'' [[AuthorsSavingThrow were eventually properly remastered and reissued on digital and physical platforms]].
** The original pre-order version of "Black Swan" off the 2007 album ''United Abominations'' has yet to see the light of day as a single or even as a bonus track on the 2019 reissue of the album. [[note]] While it was later released on their ''[=TH1RT3EN=]'' album, it was a different recording from the one heard in 2007. [[/note]]
** The bands original cover of "These Boots" with the altered tongue & cheek lyrics hasn’t been reissued properly on either remaster of the album, [[note]] The 2002 version has it, but there’s censor beeps over the altered lyrics, and the 2018 ''Final Kill'' version features a more faithful cover of the song. [[/note]] thus is only available on the first pressing of the album.
** Up until 2019, the five studio albums from 2001-2011 [[note]] ''The World Needs a Hero'', ''The System Has Failed'', ''United Abominations'', ''Endgame'' & ''[=TH1RT3EN=]'', [[/note]] were this as the original [=CDs=] were long out of print and in some cases costed up to $50 dollars used on sites like Amazon and eBay.
* LateExportForYou: "One Thing" and "Coming Home" were exclusive to the original Japanese editions of ''Cryptic Writings'' and ''The World Needs A Hero'' until they were released internationally on ''Warchest'' several years later. "Coming Home" was an alternate mix however, as it does not FadeIn unlike the original. The fade-in version was eventually released on the remastered version of ''The World Needs A Hero''.
* PromotedFanboy: Chris Adler was a longtime fan of the band who also counted Gar Samuelson as one of his biggest influences. He did, however, make a point of telling Mustaine that he would only be willing to appear on the album if it was sufficiently close to their classic sound as opposed to the more hard rock oriented sound heard in ''Super Collider''.
* RefittedForSequel: Many examples:
** Mustaine's songs "Jump in the Fire" and "The Mechanix" were both brought to Metallica and rewritten by them after Dave was fired from the band, whilst keeping the same riffs. Both had the lyrics completely changed, and the latter was renamed "The Four Horsemen" and slowed down. Similarly, Mustaine's song "Hangar 18" was reworked into "The Call of Ktulu" after he left the band, and riffs he wrote for another song were reused in "Leper Messiah". Megadeth would record versions of both "The Mechanix"[[note]]Renamed to simply "Mechanix"[[/note]] and "Hangar 18".
** The earliest Megadeth setlists featured "Burnt Offerings", "Blood and Honor", "Conjure Me", "Next Victim", a guitar solo named "Quicksand", in addition to an instrumental version of "Hook in Mouth". The first four songs were reworked respectively as "Set the World Afire", "Wake Up Dead", "The Conjuring" and "My Last Words". "Quicksand" was divided up into the intros to "502" and "The Skull Beneath the Skin". Lyrics were written for "Hook in Mouth" later on.
** "Evil That's Within" and "Bullprick" were both recorded during the ''Youthanasia'' sessions but left off, and were rewritten as "Sin" and "FFF" on ''Cryptic Writings'' (the remaster of which features the ''Youthanasia'' outtakes as bonus tracks). The same is true of "Vortex", but it didn't receive a significant difference in the lyrics.
** "Wanderlust" from ''Risk'' is a rearranged version of an as-yet-unreleased ''Cryptic Writings'' outtake called "Smoking Gun", something mentioned in the ''Risk'' remaster booklet.
** According to Mustaine, "Deadly Nightshade" from ''[=Th1rt3en=]'' is a completed version of an unreleased song from the ''Youthanasia'' period too.
* RoleEndingMisdemeanor:
** In the 1980s, Chris Poland was fired after selling the band's equipment for drugs.
** His replacement, Jeff Young, was fired for allegedly hitting on Mustaine's girlfriend, although he denies this to date and attributes it to Dave's drug-induced paranoia at the time.
** After a fan leaked sexually explicit videos of David Ellefson in 2021, the ensuing controversy led to his second departure, with Mustaine even deciding that someone would re-record his bass tracks that were done for the following album.
* ThrowItIn: The end of the band's cover of [[Music/BlackSabbath "Paranoid"]] includes Dave yelling "Nick...''Nick''...'''Nick!'''" to get the drummer (Menza) to stop playing, to which he responds "''Fuck. Me. Running!''"
* TroubledProduction: ''The Sick, the Dying... and the Dead!'' began production in 2019 and was delayed to late 2022 due to Mustaine's throat cancer diagnosis, the COVID-19 pandemic, and David Ellefson's termination from the band.
* WhatCouldHaveBeen:
** "Peace Sells" was supposed to be an 8+ minute epic before Gar Samuelson told Mustaine that they had an instant anthem on their hands and would benefit from cutting it down to four minutes and releasing it as a single. Samuelson was apparently the one guy in the band whose judgment Mustaine trusted more or less absolutely, and so he deferred to him and an iconic track was born.
** Sometime around the end of TheEighties, Mustaine wanted to add [[Music/{{Pantera}} Darrell Abbott]] and (possibly) [[Music/{{Metallica}} Cliff Burton]] to his formation. None of these resulted, due to the death of the latter and the former wanting to play with his brother (who is a drummer) while the drummer role was already occupied by Nick Menza. Could you imagine how awesome the band would became if said members (the Abbott brothers & Cliff) would have been members of Megadeth? See the entry on the page for details.
** Similarly, Jim Durkin (then of Dark Angel) was invited to join after Poland was kicked out and declined because he wanted to stick with Dark Angel. This is commonly misattributed to Eric Meyer, who auditioned for Young's empty slot later on, as did Lee Altus (then just in Heathen). Both of them had very distinctive styles (Meyer had a melodic, flowing style that made heavy use of Middle Eastern scales, while Altus had a very aggressive neoclassical style that was very different from Friedman's more relaxed feel) that would have likely resulted in a much different sound. Both were apparently offered the job; Altus declined because of Mustaine's out-of-control drug usage, and the same was likely true for Meyer.
** At several points later on, Music/JeffLoomis and Rusty Cooley were both offered spots. The former had auditioned long, long before that when he was still a teenager and had gone on to become a big name in his own right with Music/{{Nevermore}}; he declined for obvious reasons, as Nevermore was still an active touring band at that time and he was also working on ''Zero Order Phase'', but he recommended Broderick and the rest was history (which was the second time that someone wound up joining Megadeth because of Jeff). Cooley, meanwhile, was contacted after Broderick left; while joining Megadeth had apparently been a childhood dream of his, he declined largely because he didn't feel comfortable with playing other people's music and didn't want to feel like he was a glorified cover band artist (though his desire for his daughter to not have an absentee father also played a part).
** At some point before Loureiro's hiring, Chris Adler had strongly suggested Greg Burgess of Allegaeon for the lead guitar spot; while Mustaine wound up going with Loureiro, it was certainly within the realm of possibility.
** Their cover of the VideoGame/DukeNukem theme, "Grabbag", was going to be part of ''VideoGame/DukeNukemForever'''s soundtrack. Due to changes made during [[DevelopmentHell the game's protracted development history]], it was replaced in the finished product by Eric Von Rothkirch's cover of the song. To rescue it from being a LongSongShortScene, it was included in ''Duke Nukem: Music To Score By'', the Japanese edition of ''Risk'', and several compilations such as ''Warchest'' (none of which call it by its proper name, "Grabbag", and just refer to it as "Duke Nukem" instead).[[note]]The 2022 leak of the 2001 E3 demo build of ''Forever'' revealed that the Megadeth version of the song was included in the game files; had the game released when it was originally intended to, the song likely would've been included in the finished product.[[/note]]
** On the same vein, "Gears of War" wasn't finished for the time of [[VideoGame/GearsOfWar the game]]'s launch, though [[http://i41.tinypic.com/zwz59s.jpg the coverart]] for the single depicts the game's logo and typographied name. The song was included in ''United Abominations'', and the single was released, anyway.
** Early tracklistings for ''United Abominations'' include "The Bodies Left Behind" as one of two pre-order bonus tracks. In the end, the only bonus track was "Black Swan". "The Bodies Left Behind" is likely to be the same track recorded for ''Endgame'' as "Bodies", and whether or not it is, it would be interesting to hear this particular recording.
** According to Dave, he reached out to Marty Friedman and Nick Menza about doing a 25th anniversary tour in honor of the release of ''Rust In Peace'', but the talks fell through. When Shawn Drover and Chris Broderick found out, they were so offended they decided to leave (the poor reception to ''Super Collider'' didn't help). The band fortunately recovered, but Dave took full responsibility for his mis-handling of the situation.
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