Ori and the Blind Forest: Definitive Edition

One Life difficulty is exactly that: you get one life, and if you die, you start from the beginning. However, you can use the same trick for this mode as you did with the "Immortal" achievement in the original version of the game. Play the game offline for a short while, and when you've made a small chunk of progress, go online so that your game syncs to the cloud. Go offline again and continue to play, rinsing and repeating this process as you feel necessary.

If you die while playing offline, you can delete your local save AND the game's reserve space (this part is very important as this is what tracks your deaths) and sign back into Live. This will sync your game with the cloud, downloading the last save you made while online. You'll lose some progress, but this is much better than having to do the entire game with no deaths for real, unless you truly want to master the game.