Jojo's Bizarre Adventure: Phantom Blood

Extra Battle mode:
Successfully complete Story mode. The game can be replayed with different characters appearing in various levels.

77 Ring Knights mode:
Complete five Extra Battle mode levels. You must defeat 77 opponents in succession.
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Every time 77 Ring Knights mode is completed you will unlock a new character for that mode. Complete 77 Ring Knights the indicated number of times to unlock the corresponding character.

William Zeppeli: One time.
Robert Speedwagon: Two times.
Dire: Three times.
Straizo: Four times.
Tonpetti: Five times.
Johnathan with Luck and Pluck: Six times.
Tuxedo Johnathan: Seven times.
Wang Chan: Eight times.
Jack the Ripper: Nine times.
Bruford: Ten times.
Tarkus: Eleven times.
Mr. Adams: Twelve times.
Doobie: Thirteen times.
Dio: Fourteen times.
Wang Chan with Dio's Head: Fifteen times.

Dio mode:
Successfully complete all the default battles in Extra Battle mode. Alternately, successfully complete Story mode using all unlocked characters. To unlock the last Extra Battle mode battle, you must also complete 77 Ring Knights mode with four characters. Complete the last Extra Battle mode battle to unlock Dio mode. You can now replay Story mode as Dio.