Maybe doing something in the vein of The Witness. The style of puzzle you're currently doing could be one of them, expanding what is possible as the game goes on. Maybe even being able to interact with the items you trade, pulling them apart, etc. Then after a few levels you could introduce a different style of puzzle. Less inventory size-based, just to give more of your artstyle and ideas as they seem really awesome. Maybe even have past puzzles interacting with future puzzles. Even allowing us to walk down the previous hallways to attain older items that might be used in a different way in the new puzzles.
Ya know, easy stuff. XD (This is sarcasm, I get this would be a very difficult thing to create and balance, besides the inherent difficulty of puzzle design itself.)