In the folder C:Users[User name]AppDataLocalBladesOfTime loof for a the file settings.blk. This file can be opened with a plain text editor like Notepad. Within this file, there's a section called "game_start". Modify the following variables (or add them if they are not there) to enable the cheats.

Effect	Code
God mode. Does not prevent scripted deaths like falling into pits.	godmode:b=yes
One-hit-kill enemies. May prevent from completing some tutorial events if they require you to lower the health of an enemy.	devastation:b=yes