Here is the full list of all 15 Siren Head: Awakening achievements.
Find the sh***** graffiti.
Collect all the car parts in one game.
Repair the broken-down car.
Escape with the repaired car.
Collect all the survivor notes in one game.
Unlock the secret bunker.
Collect the 5th note found in the secret bunker.
Commit suicide with the gun found in the secret bunker.
Set up siren head's trap at the gas station.
Kill siren head using the gas station trap.
Complete the game in normal mode.
Complete the game in baby mode.
Complete the game in hard mode.
Collect all the car parts and survivor notes in one game.
Collect 5 flashlight batteries in hard mode in one game.