Young Alex Costume
From the game’s main menu and insert the following code on the directional pad to unlock the Young Alex costume:

Up, Up, Down, Down, Left, Right, Left, Right, Circle

Circular Saw
On a subsequent play session, find it in the Shepherd family's garage.

Hospital Ending and Orderly Costume
Spare the mother in the prison, and forgive the father at the confessional.

Opt to save Wheeler by giving him a first aid kit.

You will unlock the Hospital Ending and the orderly (scrubs) costume.

Drowned Ending and Cult Costume
Kill the mother in the prison, and blame the father at the confessional.

Opt to save Wheeler by giving him a first aid kit.

You will unlock the Drowning Ending and the cultist costume.

U.F.O. Ending, Sheriff Costume, and Laser Gun
Spare the mother in the prison, and blame the father at the confessional.

Opt to save Wheeler by giving him a health drink.

You will unlock the U.F.O. Ending, the sheriff costume and the Laser Gun (find on subsequent session in Joshua's room).

Best Ending and Travis Costume
Kill the mother in the prison, and forgive the father at the confessional.

Opt to save Wheeler by giving him a first aid kit.

You will unlock the Best Ending and the trucker costume of Travis Grady.

Bogeyman Ending and Bogeyman Mask
Spare the mother in the prison, and blame the father at the confessional.

Allow Wheeler to die when you find him (after defeating Curtis).

You will unlock the Bogeyman Ending and the Bogeyman mask.