Materials, tool and die would be the problem. Medical and sanitation would be improvements. Force multipliers should be simple to build but then we are back to the original problem. Consider, I want to build a simple low pressure boiler. To do so I need to be able to weld or solider. For that I need point heating. So let’s say I know how to make acetylene. How would I compress it? If I could compress it how could I store it? See how the issues compound? And how would I not get burned at the stake for witchcraft?
Very carefully. Acetylene is dissolved in acetone in a ceramic sponge under pressure. Get just the gas at too high a pressure and it will reconfigure its structure with a sudden release of heat and likely destroy your workshop.