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