The easiest way to savescum is copy-pasting in a seperate folder. However, the game is a lot less fun if it isn't insanely hard anymore. And if you savescum, I will look angrily in your direction
. There is indeed no neck bodypart, and sadly, .50 is the latest version, even though there have been some expansions/mods. Try
Livan (Lampshades Ivan),
Ivan CVS (no idea what that stands for) or
I vant more Ivan (for the links and info, check the Ivan forum). You have HP, which is how long you can hold out against a combination of poison, wounds, fire, and HFS, and every bodypart has seperate HP, which adds up to your total. Bloodsheder, IIRC the exact HP for each bodypart is not yet confirmed.
Dexterity increases chance to hit, the body part you hit depends mostly on the weapon. Accurate weapons (daggers, whips) will target limbs more often (I guess this resembles striking knees, shoulders, and other joints). I don't think dex changes the target body part, only the weapon currently held. It is notper se a bad thing to strike at the limbs, as this greatly reduces your opponents effectiveness and takes less wounds than torso or groin and less luck than head.
Engraving the name of some elven queen or godess is indeed nethack, and not Ivan, where engraving is purely for style (monsters can engrave things like 'golem needs master', and your character is an instance of the same class monsters are from.)
As Rickvoid said, great health is not great, but you don't really need to keep max-health very low. Under 200 hp should be okay (over 200 enables a certain clown).
I have never been decapitated by a porcupine that I remember, but I don't think there are that many bugs left.
The forum Rickvoid was talking about:
www.attnam.com, it has lots of information and a wiki. And lots of drunk posts and the like in the spam section. Avoid that place.