Why were guns so often pointed against gods like they are supposed to be a deadly threat? The more powerful gods are usually shown as bulletproof. Even the weaker ones have a powerful enough healing factor that would in a minute or two heal multiple bullet shots. Worse is the guns are often from pointed at gods from people who should know better like Delphyne Gorgon and Vali Lokison. She pointed guns at a full-power Hera and Hephaestus expecting them to be a major threat. Neptune was at least mysteriously powered-down. Vali tried using "mistletoe" bullets, but why would that matter? Mistletoe was a specific vulnerability to Balder not gods in general.
Why was Neptune so weak from his prolonged stay on Earth? From time to time writers state gods are weaker on Earth then their home dimension though this isn't always consistent. Yet Ares showed no signs of weakening or at least not to nearly the same degree. Same with the other gods like Pluto and Hera.