Here are some cheats and tips for the game Siren.
Zuno puzzle mini-game:
Find Archive 087 in Kyoya Sudo’s stage (03:00 on Day 3).
Time attack mode:
Successfully complete the first two objectives on all levels in every scenario.
Mission Objectives 2:
To unlock Mission Objectives 2 for every character and/or scenario, complete
19 stages in any order. Then, press L1 + R1 while the stage is highlighted at
the scenario selection screen. Note: You will automatically obtain it after
completing the random 19 stages.