Pokemon changes

Moves learned

PokemonChange
SnivyLearns Vine Whip at Lv 6 (was 7).
TepigLearns Ember at Lv 6 (was 7).
OshawottLearns Water Gun at Lv 6 (was 7).
PurrloinLearns Pursuit at Lv 13 (was 15).
Porygon lineNo longer learns Conversion (replaced by Flip Turn in the move slot).
Evolved PokemonCan learn their pre-evolutions' egg moves from the Day-Care Lady (Route 3, costs a Lucky Egg); the Pichu line can also get Volt Tackle.

Hidden abilities

PokemonNew hidden abilityWas
Venipede, Whirlipede, ScolipedeSpeed BoostQuick Feet

Normal abilities

PokemonAbilities
TorkoalWhite Smoke or Drought (new); hidden ability Shell Armor, as in vanilla
Roggenrola, BoldoreSturdy or Weak Armor (new); hidden ability Sand Force, as in vanilla
GigalithSturdy or Sand Stream (new); hidden ability Sand Force, as in vanilla
Wingull, PelipperKeen Eye or Drizzle (new); hidden ability Rain Dish, as in vanilla

Wild held items

Chansey, Blissey and Happiny no longer hold Lucky Eggs in the wild, and Luvdisc no longer holds a Heart Scale.

Gift Pokemon

You get a Pikachu (Lv 5) with your starter. It has Lightning Rod as a hidden ability, which it keeps through evolution, and knows Fake Out.