How does the save system work in Little Nightmares?
The game saves automatically and you can trigger autosave by lighting a torch or a candle found in specified areas in the game:
Unfortunately when I died, I didn't start from this location but an earlier area. The game had still saved as the torch was lit.
Solution 1:
It appears that lamps aren't checkpoints. The saving icon appears when lighting a lamp, but the game most likely saves to keep track of lit torches and candles for the "Light Up Your Life" achievement.