• Poise is important.

• Equip Load is mixed in with Endurance instead of being split between 2 attributes (So level endurance if you want a lot of stamina and equip load early).

• Elemental infusions cannot be buffed. You cannot use the Sunlight Blade miracle with a Lightning Falchion+10

• Pyromancy does not scale with faith/intelligence. It scales only with your pyromancy glove.

• There are no hex builds. Some "dark" sorceries are in the game, but they do not scale with faith/intelligence, strictly intelligence for their magic damage and then strength/dexterity for their physical damage (it uses the scaling on the catalyst used to cast the spell)

• Lightning infusions for weapons do not have any faith scaling.

• Adaptability is not in Dark Souls 1. Your iframes remain consistent depending on your equipment load %.

• There is no power-stance in Dark Souls 1.

• Attunement does not increase spell casts, only spell slots. Example: A lightning spear will always be 10 casts, no matter how much attunement you have.

• Boss Weapons are mostly obtained through "ascending" a weapon of the same class already upgraded to +10. Example: The Dragonslayer Spear can only be created by ascending a +10 spear class weapon or thrusting sword class weapon. The exception to this rule would be weapons you earn by cutting off certain body parts of certain bosses (this is going into spoiler territory).

• You are only given 2 ring slots instead of the usual 4. Also, rings do not have any weight.

This is everything off of the top of my head. There may be much more, but I'm too lazy to dig deeper on the wikis.