"Awake" zombies are more attentive and can hear you at much longer ranges than sleepers.
An unsuppressed rifle can get you a lot of attention.
Oh, it was funny the first time - not when people repeat the exact same joke over and over.
The whole smelting materials into the forge (smelter) is a silly mechanic that is unnecessarily hard to understand because no smelter works that way IRL.
They do not store a huge quantity of 5 different materials internally.
You smelt something and then you have an output of material so the chem station setup would be a lot more realistic for it.
That changes nothing with the gameplay. You need fuel to turn raw ores and other smeltables into ingots.