Every bullet and herb counts. Only engage enemies when necessary; sometimes, running past is the best option. Combine herbs strategically (Green + Red for maximum healing). Don't use powerful ammo on regular zombies. Save your Magnum/Grenade Launcher rounds for Lickers, G-Adults, and bosses. Always check every room thoroughly for hidden ammo and gunpowder. Crafting gunpowder into ammo is essential, so prioritize collecting it. Only carry what you need for the immediate area, storing the rest in item boxes.
