Unlock Secret Achievements.
The following is a list of Secret Achievements and how to unluck them.

0 Gamerscore Points:
Lose 5 Online matches in a row.

0 Gamerscore Points:
Lose 10 Online matches in a row.

0 Gamerscore Points:
Lose 20 Online matches in a row.

0 Gamerscore Points:
Achieve a grade 'D' in Dead or Alive 4 Online.

0 Gamerscore Points:
Achieve a grade 'E' in Dead or Alive 4 Online.

Achieve a Bronze Star - 10 Gamer Points:
Beat someone with a 10-14 win streak in Dead or Alive 4 Online.

Achieve a Silver Star - 20 Gamer Points:
Beat someone with a 15-19 win streak in Dead or Alive 4 Online.

Achieve a Gold Star - 30 Gamer Points:
Beat someone with a 20+ win streak in Dead or Alive 4 Online.

50 Wins in Dead or Alive 4 Online - 20 Gamerscore Points:
Win 50 games accumulatively in Dead or Alive 4 Online.

Rank B in Dead or Alive 4 Online - 20 Gamerscore Points:
Win enough Dead or Alive 4 Online games to achieve this rank. ALL Items in Survival Mode - 25 Gamerscore Points:
Collect ALL items in Survial mode.

Play Dead or Alive 4 for 5 hours - 10 Gamerscore Points:
5 Hours Played

Play Dead or Alive 4 for 10 hours - 20 Gamerscore Points:
10 Hours Played

Play Dead or Alive 4 for 100 hours - 40 Gamerscore Points:
100 Hours Played


Unlockable Costumes

Unlock Leon - 10 Gamerscore Points:
Complete Story mode with Zack.

Unlock Ein - 10 Gamerscore Points:
Complete Story mode with Hitomi.

Unlock Gen Fu - 10 Gamerscore Points:
Complete Story mode with Eliot.

Unlock Helena - 20 Gamerscore Points:
Complete Story mode with ALL characters.

Unlock Nicole (Spartan-458) - 20 Gamerscore Points:
Complete story mode with Helena.

Unlock Tengu - 20 Gamerscore Points:
Complete Time-Attack mode with ALL the characters including the secret characters.

Unlock ALL Costumes - 50 Gamerpoints:
Unlock ALL costumes including secret characters for every character.


Unlock Nassau Station:
A hidden sparring stage which just has a floor mat with no walls becomes available when Nicole (Spartan-458) is unlocked

Unlockable Characters

Leon:
Beat Story mode with Zack.

Ein:
Beat Story mode with Hitomi.

Gen Fu:
Beat Story mode with Eliot.

Nicole (Spartan):
Beat Story mode with Helena.

Helena:
Beat Story mode with ALL 16 characters.

Tengu:
Beat Time attack for ALL characters, including unlockables.


Unlock Nassau Station Stage:
This stage becomes available when Nicole (Spartan-458) has been unlocked


Unlockable Costumes

Beat story mode once with a character to unlock their costume which can be used in Story mode, their are 16 default plus Helena. Beat Time Attack mode with default settings on any difficulty for characters that can't be used in Story mode.

Bayman C3:
Beat Story mode with him one time per costume.

Brad Wong C3:
Beat Story mode with him one time per costume.

Ein C3-C4:
Beat Time Attack mode with him one time per costume.

Genfu C3-C4:
Beat Time Attack mode with him one time per costume.

Leon C3-C4:
Beat Time Attack mode with him one time per costume.

Christie C3-C4:
Beat Story mode with her one time per costume.

Elliot C3-C4:
Beat Story mode with him one time per costume.

Hayabusa C3-C4:
Beat Story mode with him one time per costume.

Hayate C3-C4:
Beat Story mode with him one time per costume.

Bass C3-C4:
Beat Story mode with him one time per costume.

Jann Lee C3-C4:
Beat Story mode with him one time per costume.

Zack C3-C4:
Beat Story mode with him one time per costume.

Helena C3-C5:
Beat Story mode with her one time per costume.

La Mariposa C3-C5:
Beat Story mode with her one time per costume.

Tina C3-C5:
Beat Story mode with her one time per costume.

Ayane C3-C6:
Beat Story mode with her one time per costume.

Leifang C3-C7:
Beat Story mode with her one time per costume.

Kasumi C3-C7:
Beat Story mode with her one time per costume.

Kokoro C3-C7:
Beat Story mode with her one time per costume.

Nicole (Spartan-458) C3-C7:
Beat Time Attack mode with her one time per costume.

Hitomi C3-C8:
Beat Story mode with her one time per costume.