Let's see - significant changes to several things
Races
Gnomes & Halflings are different (no arcane casting for halflings, gnomes do not gain any free spells, but gain did stat raises)
Lizardfolk and Half-ogres as a "core" race
Classes
Druids are folded into the Priest Class
Cleric: A Different Priest Class for Each Power
Paladin: Paladins have to be dedicated to a specific god, different spell lists (and some abilities) depending on the god.
Monk: Uses my system for martial arts styles - only 2 kinds of monks availble to characters of the "Occidental" portion of the setting.
Ranger: Another alt.ranger
Bards: Cannot just choose spells, must find them in songbooks, learn them from other bards, convert them from wizard spells, research them, etc. . .
Wizards: Gain 1 new spell every two levels (not 2 every 1), otherwise have to learn, steal, beg or borrow spells.
NO SORCERERS (a variant witch class instead)
Barbarian: This is a class based on cultural type - so taking it is limited.
Combat
Armor vs. Weapons Type (slashing, peircing, blunt)
Critical Hit/Fumble Result Tables
Knockdown Dice for weapons
Base Defense Bonus: AC improves with level based on class. BDB is lost if deprived of Dex.
Dying: Characters don't die until reaching the negative equivalent of 1/2 their max hit points + 10
Stabilizing: Only 5% chance
While at Negs: Any damage done to someone at negs calls for a FORT save (10 + damage done) or die
Magical Healing: Those brought back from "death's door" by means of magical healing (not rest) are exhausted until having one hour's rest and then fatigued until 8 hours of rest
Feats/Skills
3E version of Power Attack
First Aid: take 1d10+10 rounds to perform
There is lots more, but that is a taste.