Arcade Mode Special Endings

* In order to reach New Challenger CPU Opponent, first make sure your matches are set for three rounds. Then, without continuing, get three Critical-Art finishes before the end of the fourth match. After this, you will face your mid-boss. This can be done on easy difficulty (though I'm unsure if the number requirement for CA finishes is the same on higher difficulties). Perfects are not needed. NOTE: this seems to change based on which character path you take. I'm looking into finalizing specific requirements.

* In order to face Shin Gouki (secret final boss), do not lose any rounds and get at least five Critical-Art finishes (I believe it's five). I'm unsure if he's the secret boss for all games. He can be reached on easy difficulty, though he will be his usual brutal self. If you lose to him, you will still beat arcade mode. You cannot continue versus him if you do lose.

* For the 1 Straight Victory requirements, this means winning matches without losing a round. This cannot be done with one-round matches.

* I do not know how to get the Hell difficulty needed for some of these. I imagine you'll have to beat Hard first. Or Shin Gouki. *shrug*

Missing Endings

* As of early 2021, it appears this gallery is 100% complete! If my tallying is correct, this equals 172 high-res images spanning the series' entire history. As season 5 rolls out, more will be added.

* Many thanks to everyone who has submitted images. Credits are listed at the bottom.

Special Endings By Game
Street Fighter
Fighter Difficulty Requirements Details Image
Abigail Hard n/a SF Legacy (Shinkiro)
Balrog Hard No Continues SF Legacy (Bengus)
Birdie Hard n/a SF Legacy (SF Artwork)
Cody Hard n/a SF Legacy (Shinkiro)
Ken -any- No Continues Special Artwork (Tamio)
Ken Hard No Continues SF Legacy (Shinkiro)
Lucia Hard n/a SF Legacy (Ukabin)
Poison Hard n/a SF Legacy (Final Fight Artwork)
Ryu -any- No Continues Special Artwork (Bengus)
Ryu Hard n/a SF Legacy (Bengus)
Sagat Hard n/a SF Legacy (Shinkiro)
Zeku Hard n/a SF Legacy (Ikeno)
Street Fighter II
-Any Fighter- Easy Perfect On Bonus Stage SF Legacy (Akiman)
-Any Fighter- Normal Perfect On Bonus Stage SF Legacy (Shoei)
-Any Fighter- Hard Perfect On Bonus Stage SF Legacy (Kinu Nishimura)
-Any Fighter- Hard Defeat New Challenger CPU Opponent SF Legacy (Kinu Nishimura)
-Any Fighter- Hell Perfect On Bonus Stage SF Legacy (Kinu Nishimura)
Akuma -any- No Continues Special Artwork (Katsuya Terada)
Akuma -any- Defeat New Challenger CPU Opponent SF Legacy (Bengus)
Balrog -any- Defeat New Challenger CPU Opponent SF Legacy (Akiman)
Blanka Hard n/a SF Legacy (Daichan)
Cammy -any- Defeat New Challenger CPU Opponent SF Legacy (Edayan)
Cammy Hard No Continues SF Legacy (Bengus)
Cammy Hard No Continues SF Legacy (Tatsuya Yoshikawa)
Chun-Li -any- No Continues Special Artwork (Fuzichoco)
Chun-Li -any- Defeat New Challenger CPU Opponent SF Legacy (Akiman)
Chun-Li -any- No Continues / 1 Straight Victory Special Artwork (Grape Brain)
Chun-Li -any- No Continues / 2 Straight Victories Special Artwork (Akihiro Yamada)
Chun-Li -any- No Continues / 3 Straight Victories Special Artwork (Green House Yonezawa/Hyodo)
Chun-Li -any- No Continues / 4 Straight Victories Special Artwork (Krenz)
Chun-Li Hard n/a SF Legacy (Bengus)
Dhalsim -any- Defeat New Challenger CPU Opponent SF Legacy (Bengus)
E. Honda -any- No Continues Special Illustration (Yumi Tada)
Guile -any- Defeat New Challenger CPU Opponent SF Legacy (Shinkiro)
Ken -any- Defeat New Challenger CPU Opponent SF Legacy (Kinu Nishimura)
Ken Hard No Continues SF Legacy (Bengus)
M. Bison -any- Defeat New Challenger CPU Opponent SF Legacy (Kinu Nishimura)
M. Bison -any- No Continues Special Artwork (Misawo Akutagawa)
Ryu -any- No Continues Special Artwork (Green House Yonezawa/Hyodo)
Ryu -any- No Continues / 1 Straight Victory Special Artwork (Akio)
Ryu -any- Defeat New Challenger CPU Opponent SF Legacy (Bengus)
Ryu Hard n/a SF Legacy (Bengus)
Sagat -any- Defeat New Challenger CPU Opponent Special Artwork (Kitajima Submission)
Vega -any- No Continues Special Artwork (Chisato Mita)
Vega Hard n/a SF Legacy (Bengus)
Zangief -any- Defeat New Challenger CPU Opponent SF Legacy (Ikeno)
Street Fighter Zero/Alpha
-Any Fighter- Hard No Continues SF Legacy (Bengus)
-Any Fighter- Hard No Continues SF Legacy (Edayan)
Akuma -any- Defeat New Challenger CPU Opponent SF Legacy (Daichan)
Akuma Hard No Continues SF Legacy (Ikeno)
Balrog -any- Defeat New Challenger CPU Opponent SF Legacy (Ikeno)
Birdie -any- No Continues Special Artwork (Yomeoka)
Birdie -any- Defeat New Challenger CPU Opponent SF Legacy (Bengus)
Blanka Hard Defeat New Challenger CPU Opponent SF Legacy (Hideki)
Cammy -any- Defeat New Challenger CPU Opponent SF Legacy (Bengus)
Chun-Li -any- Defeat New Challenger CPU Opponent SF Legacy (Daichan)
Cody -any- No Continues Special Artwork (Eri Nakamura)
Dan -any- Defeat New Challenger CPU Opponent Special Artwork (Miki Kobayashi)
Dhalsim -any- Defeat New Challenger CPU Opponent SF Legacy (Bengus)
E. Honda Hard n/a Special Artwork (Kei Ichimonji)
Guile -any- Defeat New Challenger CPU Opponent SF Legacy (Ikeno)
Kage -any- No Continues SF Legacy (Edayan)
Karin -any- No Continues Special Artwork (Masahiro Nakahira)
Karin -any- Defeat New Challenger CPU Opponent SF Legacy (Edayan)
Karin Hard n/a SF Legacy (Bengus)
Ken -any- Defeat New Challenger CPU Opponent SF Legacy (Ikeno)
Ken Hard n/a SF Legacy (Daichan)
M. Bison -any- Defeat New Challenger CPU Opponent SF Legacy (Togachi)
Nash -any- Defeat New Challenger CPU Opponent SF Legacy (Edayan)
R. Mika -any- Defeat New Challenger CPU Opponent SF Legacy (Ikeno)
R. Mika Hard n/a SF Legacy (Edayan)
Ryu -any- Defeat New Challenger CPU Opponent SF Legacy (Bengus)
Ryu Hard n/a SF Legacy (Daichan)
Ryu Hard No Continues SF Legacy (Bengus)
Sagat Hard n/a Special Artwork (Ikeno)
Sakura -any- No Continues Special Artwork (Hajime Ueda)
Sakura -any- No Continues / 1 Straight Victory Special Artwork (Namboku)
Sakura -any- Defeat New Challenger CPU Opponent SF Legacy (Bengus)
Sakura Hard n/a SF Legacy (Bengus)
Sakura Hard No Continues SF Legacy (Kinu Nishimura)
Sakura Hard 1 Straight Victory SF Legacy (Daichan)
Vega -any- Defeat New Challenger CPU Opponent SF Legacy (Haruman)
Zangief -any- Defeat New Challenger CPU Opponent SF Legacy (Edayan)
Street Fighter III
-Any Fighter- Easy Perfect On Bonus Stage SF Legacy (Ikeno)
-Any Fighter- Normal Perfect On Bonus Stage SF Legacy (Ikeno)
-Any Fighter- Hard Perfect On Bonus Stage SF Legacy (Kinu Nishimura)
-Any Fighter- Hell Perfect On Bonus Stage SF Legacy (Kinu Nishimura)
Akuma Hard n/a SF Legacy (Kinu Nishimura)
Alex -any- No Continues Special Artwork (D. KURITA)
Chun-Li -any- No Continues Special Artwork (Marthe)
Gill -any- 5 Straight Victories Special Artwork (Musashimaru)
Ibuki -any- No Continues Special Artwork (Kitasenri)
Ken -any- No Continues Special Artwork (toi8)
Kolin Hard n/a SF Legacy (Akiman)
Laura Hard n/a SF Legacy (Harumaru)
Poison -any- 5 Straight Victories SF Legacy (Akiman)
Ryu Hard n/a SF Legacy (Kinu Nishimura)
Urien -any- No Continues Special Artwork (Downmansayman)
Street Fighter IV
-Any Fighter- Hard No Continues SF Legacy (Take)
-Any Fighter- Hard 1 Straight Victory SF Legacy (SFIV Artwork)
-Any Fighter- Hard 2 Straight Victories SF Legacy (Kinu Nishimura)
-Any Fighter- Hard 3 Straight Victories SF Legacy (Kinu Nishimura)
Akuma -any- Defeat New Challenger CPU Opponent SF Legacy (Polygon Pictures)
Balrog -any- Defeat New Challenger CPU Opponent SF Legacy (Polygon Pictures)
Blanka -any- Defeat New Challenger CPU Opponent SF Legacy (Kinu Nishimura)
Cammy Hard No Continues SF Legacy (Noizi Ito)
Cammy -any- Defeat New Challenger CPU Opponent SF Legacy (Hiroaki)
Chun-Li -any- Defeat New Challenger CPU Opponent SF Legacy (Tamio)
Chun-Li Hard No Continues SF Legacy (Yuri Kataiwa)
Cody -any- Defeat New Challenger CPU Opponent SF Legacy (Polygon Pictures)
Dan -any- No Continues Special Artwork (Masazaku Ishiguro)
Dhalsim -any- Defeat New Challenger CPU Opponent SF Legacy (Ikeno)
Dhalsim Hard n/a SF Legacy (Polygon Pictures)
E. Honda Normal No Continues SF Legacy (Akiman)
E. Honda or Poison Easy No Continues SF Legacy (Akiman)
Guile -any- Defeat New Challenger CPU Opponent SF Legacy (Akiman)
Ibuki -any- Defeat New Challenger CPU Opponent SF Legacy (Polygon Pictures)
Juri -any- No Continues Special Artwork (Yusuke Nakamura)
Juri -any- Defeat New Challenger CPU Opponent SF Legacy (Polygon Pictures)
Kage -any- Defeat New Challenger CPU Opponent SF Legacy (Kinu Nishimura)
Ken -any- Defeat New Challenger CPU Opponent SF Legacy (Polygon Pictures)
M. Bison -any- Defeat New Challenger CPU Opponent SF Legacy (Polygon Pictures)
Poison Normal No Continues SF Legacy (Akiman)
Ryu Hard n/a SF Legacy (Ikeno)
Ryu -any- Defeat New Challenger CPU Opponent SF Legacy (Ikeno)
Ryu Hard No Continues SF Legacy (Tamio)
Sagat Normal No Continues Special Artwork (Hinanana)
Sakura -any- Defeat New Challenger CPU Opponent SF Legacy (Kinu Nishimura)
Seth Normal No Continues Special Artwork (Yusuke Murata)
Vega -any- Defeat New Challenger CPU Opponent SF Legacy (Kinu Nishimura)
Zangief -any- Defeat New Challenger CPU Opponent SF Legacy (Polygon Pictures)
Zangief Hard n/a SF Legacy (Ikeno)
Street Fighter V
-Any Fighter- Easy Perfect On Bonus Stage SF Legacy (Bengus)
-Any Fighter- Normal Perfect On Bonus Stage SF Legacy (Kiki)
-Any Fighter- Hard Perfect On Bonus Stage SF Legacy (Kiki)
-Any Fighter- Hell Perfect On Bonus Stage SF Legacy (Kiki)
Abigail or Dhalsim Hard n/a SF Legacy (Bengus)
Akuma or Zeku Hard n/a SF Legacy (Kiki)
Alex or Zangief Hard No Continues SF Legacy (Kiki)
Balrog or Birdie -any- No Continues Special Artwork (Zakkun Pop)
Blanka -any- No Continues Special Artwork (Hinanana)
Cammy -any- No Continues Special Artwork (Mago)
Chun-Li -any- No Continues Special Artwork (Ippei Gyobu)
Cody -any- No Continues Special Artwork (Betten Court)
Dan -any- 1 Straight Victory Special Artwork (AHNDONGSHIK)
E. Honda -any- Defeat New Challenger CPU Opponent Special Artwork (Kiki)
Ed Hard No Continues SF Legacy (Kiki)
Falke Hard n/a SF Legacy (Kinu Nishimura)
F.A.N.G. or Rashid -any- No Continues Special Artwork (Mine Yoshizaki)
F.A.N.G. or Rashid Hard No Continues SF Legacy (Kiki)
G -any- Defeat New Challenger CPU Opponent Special Artwork (Bengus)
Gill -any- Defeat New Challenger CPU Opponent Special Artwork (Koki)
Guile or Nash Hard No Continues SF Legacy (Kiki)
Ibuki -any- No Continues Special Artwork (Taro Minoboshi)
Juri Hard n/a SF Legacy (Bengus)
Kage Hard No Continues Special Artwork (Shinkiro)
Karin -any- No Continues Special Artwork (Kiraito)
Ken Hard No Continues SF Legacy (Kiki)
Kolin or Urien -any- No Continues Special Artwork (AHNDONGSHIK)
Laura Hard No Continues SF Legacy (Bengus)
Lucia -any- Defeat New Challenger CPU Opponent Special Artwork (Green House Yonezawa/Hyodo)
M. Bison Hard n/a SF Legacy (Kiki)
Menat Hard n/a SF Legacy (Kiki)
Necalli or Vega Hard n/a SF Legacy (Shinkiro)
Necalli -any- No Continues Special Artwork (Rensuke Oshikiri)
Poison -any- Defeat New Challenger CPU Opponent SF Legacy (Bengus)
R. Mika -any- No Continues Special Artwork (Rockin' Jelly Bean)
R. Mika Hard n/a SF Legacy (Kiki)
Ryu -any- No Continues Special Artwork (Jun Tsukasa)
Ryu -any- No Continues / 1 Straight Victory Special Artwork (Marthe)
Sagat -any- No Continues SF Legacy (Bengus)
Sakura -any- No Continues Special Artwork (Kazushi Hagiwara)
Seth -any- Defeat New Challenger CPU Opponent Special Artwork (Sakura)

Special thanks to:
Behemothbear & GuilTron / GamerVanquish / DavidPN

Also the following people/links:
Imgur / Gameranx / Terry / AG42 / ngl42398 / Phuuzz

And the following links:
Imgur / Imgur / Reddit / Reddit / Reddit / Reddit