Read through the whole manga. Couple of things I gleaned:
Gamer's Mind
It does not blunt all your emotions. Instead, the effect is that you stay cool in combat. Outside of battles, Jee-Han felt scared just fine, like when he went on a date with the sick girl and the father was watching;
More sinisterly, killing becomes less of an issue. Your morals and restraint are intact, you can feel appalled that you're not feeling more but the instinctive revulsion most people feel against killing an enemy isn't there.
Gamer's Body
The body takes visible injuries - Jee-Han was shot while under the effect of a body-strengthening skill, and it left a red mark/abrasion;
Stamina points (SP) and fatigue are mentioned, if not displayed on his status, and he gets tired like a normal person. Vitality may be the determining factor as to how many SP he has and how quickly he recovers (of course, then he learns massage, which reduces fatigue).
Combat for a gamer
Critical hits and headshots were a thing, at least in the start;
There's also poison and curse effects;
Opponents are considered to have normal anatomy for the purposes of damage. Blowing legs off is totally viable;
Buffing magic causes icons representing the spells to appear above the Gamer's head;
Weapons can take damage when wielded by the Gamer. Same goes for clothing;
Wizard is so the way to go if you have access to the Abyss Auction. Jee-Han even mentions D&D, the origin of 'linear warriors, quadratic wizards'.
Magic Systems
There's many routes to power - ki manipulation, alchemy, life magic, elemental magics, contract magic with elemental spirits and demons... basically anything goes;
They are still all considered to follow some approximation of conservation of energy - except the Gamer, who can truly create something from nothing with his item drops;
The Gamer, until he found a teacher for dualcasting, could only cast one spell at a time. At least, that was the author's explanation for not using Life Drain, a continuous spell.
Miscellaneous
The Abyss Auction is full of very, very scary people. Not only do they deal in human trafficking and slaves, they also modernised the black market by killing off their competitors.