Loot everything! Resources are vital for crafting weapon mods, Supremo upgrades, and gadgets. Prioritize collecting 'Depleted Uranium' from Anti-Aircraft Sites for Supremo upgrades. 'Gasolina' and 'Metal' are common for weapon mods. Visit workbenches frequently to see what upgrades are available. Don't hoard resources; use them to improve your gear and stay ahead of the FND.
