Verified answer

Same as with the console versions, it's all about which characters you play as:

Unlock === Beat Arcade Mode With

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Cammy === C. Viper

Dan === Sakura

Fei-Long === Abel

Gen === Chun-Li

Rose === M Bison

Sakura === Ryu

Seth === All Characters (including Akuma & Gouken)

Advanced Unlock Requirements

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Akuma

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a. Unlock above six characters

b. Face Akuma

+ No continues

+ 1/2/3/4 Perfects (*)

1 Perfect for 1 round matches

2 Perfect for 3 round matches

3 Perfect for 5 round matches

4 Perfect for 7 round matches

c. Defeat him

Gouken

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a. Clear game with Akuma

b. Watch an ending movie (don't need to finish it)

b. Start a new game

c. Choose a character with whom you've beaten the game.

d. Face Gouken

+ No continues or rounds lost

+ At least 1/2/3/4 perfects (*)

+ At least 3/5/7/9 Super/Ultra finishes (*)

+ At least 5/10/15/20 First Attacks (*)

e. Defeat him

* Like Akuma, these represent requirements when on 1/3/5/7 round matches.

Did you go through the game with those characters?