Amnesia: The Bunker

This is best done on Easy difficulty, as on Easy you will start with 9 inventory slots. Focus purely on the key items, and only collect what you need to progress. If you find yourself with a full inventory, use an item from your inventory rather than dropping it. Save regularly in case you accidentally drop an item or interact with the storage box in Administration.
There are also 7 Pocket Bags throughout the bunker that are worth collecting, as each one will grant you an extra inventory space.