PERSONA 4 SHIN MEGAMI

New Game +

Go through the main game once to unlock New Game Plus.
Unlockable How to Unlock
New Game + Finish the game once.
Ultimate Weapons

Available only in a 2nd playthrough or more, Death will sometimes hide within treasure chests. Chests containing Death will prompt you to pick between the choices to open or ignore the chest. If you choose to open the chest, you will have to fight Death, which when defeated, will drop the ultimate weapons for the characters.
Unlockable How to Unlock
Ultimate Weapons Defeat Death.
Secret Weapons

By returning to completed dungeons, you can find the characters' secret weapons. Note: No secret weapon available for Chie.
Unlockable How to Unlock
Main Character's secret weapon Defeat extra boss in Void Quest.
Yousuke's secret weapon Find in boss' den in Mysterious Shopping Street.
Yukiko's secret weapon Defeat extra boss in Yukiko's Castle.
Kanji's secret weapon Defeat extra boss in Steamy Bath House.
Kuma's secret weapon Defeat extra boss in Opera House.
Naoto's secret weapon Defeat extra boss in Secret Lab.
Unlock Izanagi-no-Okami

After completing the game with the true ending and starting a New Game+, a new fusion section will unlock and you'll be able to fuse Izanagi-no-Okami, one of the best Personas in the game.
Unlockable How to Unlock
Izanagi-no-Okami Complete the game once and start a New Game+ file.
How to find the Reaper

The Reaper drops the strongest equipment in the game. You can find him everywhere.
Unlockable How to Unlock
The Reaper Go to Magatsu Inaba in 2nd playthrough and open the regular treasure chests there (not the golden ones) , easier to find in Magatsu Inaba.
Hidden Skills

God's Judgement and Hell's Judgement
Unlockable How to Unlock
God Judgement Fuse a persona during the fusion forecast "Skill Change". Effects = 1/2 HP gone from enemies. Light.
Hell Judgement Fuse a persona during the fusion forecast "Skill Change". Effects = 1/2 HP gone from enemies. Dark.