‘Thanks for those links! :)’
My pleasure.
‘In NYS, where I live, we have something called a duty-to-retreat law on the books.’
Interestingly, the self-defence laws of our two countries are very similar on paper. We do not have a duty to retreat but we must not use unreasonable or disproportinate force. So whilst I may shoot an intuder if in imminent danger, I may not shoot one who is retreating. A good example is the well known incident of the Norfolk farmer Tony Martin being imprisoned for shooting a burglar. When you look closer at the incident, the burglar was an unarmed 16 year old minor who was shot twice in the back whilst running away.
If you kill a person in self-defence in the UK the law requires you to be mandatorily arrested and released on police bail whilst the incident is investigated. A court must agree it was self-defence, not just the attending police officers.
These laws, in the US, are not homogenious. They vary from state to state, and from county to county.
In some places, it is legal to shoot trespassers at night - in others, it is pretty much illegal to own a gun, period.