Obtain your starter Pikachu
Obtain Caterpie
Obtain Metapod
Obtain Butterfree
Obtain Pidgey
Obtain Pidgeotto
Obtain Pidgeot
Obtain Rattata
Obtain Raticate
Obtain Spearow
Obtain Fearow
Obtain Nidoran Female
Obtain Nidorina
Obtain Nidoran Male
Obtain Nidorino
Obtain Mankey
Obtain Primeape
Defeat Brock and Obtain the Boulder Badge with all 17 available Pokemon
Obtain Bulbasaur
Obtain Ivysaur
Obtain Venusaur
Obtain Charmander
Obtain Charmeleon
Obtain Charizard
Obtain Sandshrew
Obtain Sandslash
Obtain Nidoqueen, Nidoking, Clefable, or Wigglytuff [First Moon Stone Use]
Obtain Nidoqueen, Nidoking, Clefable, or Wigglytuff [Second Moon Stone Use]
Obtain Clefairy
Obtain Jigglypuff
Obtain Zubat
Obtain Golbat
Obtain Oddish
Obtain Gloom
Obtain Paras
Obtain Parasect
Obtain Venonat
Obtain Venomoth
Obtain Diglett
Obtain Dugtrio
Obtain Abra
Obtain Kadabra
Obtain Bellsprout
Obtain Weepinbell
Obtain Geodude
Obtain Graveler
Obtain Drowzee
Obtain Hypno
Obtain Magikarp
Obtain Gyarados
Obtain Mr. Mime
Defeat Misty and Obtain the Cascade Badge with all 50 available Pokemon
Obtain Nidoqueen, Nidoking, Clefable, or Wigglytuff [Third Moon Stone Use]
Obtain Nidoqueen, Nidoking, Clefable, or Wigglytuff [Fourth Moon Stone Use]
Obtain Vulpix
Obtain Ninetales
Obtain Vileplume
Obtain Poliwag
Obtain Poliwhirl
Obtain Poliwrath
Obtain Machop
Obtain Machoke
Obtain Machamp
Obtain Victreebel
Obtain Tentacool
Obtain Tentacruel
Obtain Ponyta
Obtain Rapidash
Obtain Magnemite
Obtain Magneton
Obtain Farfetch'd
Obtain Doduo
Obtain Dodrio
Obtain Shellder
Obtain Cloyster
Obtain Gastly
Obtain Haunter
Obtain Onix
Obtain Krabby
Obtain Kingler
Obtain Exeggcute
Obtain Exeggutor
Obtain Cubone
Obtain Marowak
Obtain Hitmonlee or Hitmonchan
Obtain Rhyhorn
Obtain Rhydon
Obtain Chansey
Obtain Tangela
Obtain Kangaskhan
Obtain Horsea
Obtain Seadra
Obtain Goldeen
Obtain Seaking
Obtain Staryu
Obtain Starmie
Obtain Scyther
Obtain Pinsir
Obtain Tauros
Obtain Lapras
Obtain Eevee
Obtain Vaporeon, Jolteon, or Flareon
Obtain Porygon
Obtain Snorlax
Obtain Dratini
Obtain Dragonair
Obtain Dragonite
Defeat Koga and Obtain the Soul Badge with all 105 available Pokemon
Obtain Psyduck
Obtain Golduck
Obtain Growlithe
Obtain Arcanine
Obtain Slowpoke
Obtain Slowbro
Obtain Seel
Obtain Dewgong
Obtain Grimer
Obtain Muk
Obtain Voltorb
Obtain Electrode
Obtain Ditto
Obtain Omanyte or Kabuto
Obtain Omastar or Kabutops
Obtain Aerodactyl
Obtain Zapdos
Defeat Lt. Surge and Obtain the Thunder Badge with all 122 available Pokemon
Obtain Squirtle
Obtain Wartortle
Obtain Blastoise
Defeat Erika and Obtain the Rainbow Badge with all 125 available Pokemon
Obtain Articuno
Defeat Either Sabrina or Blaine with all 126 Pokemon Available
Defeat Giovanni and Obtain the Earth Badge with all 126 available Pokemon
Obtain Moltres
Defeat the Elite Four and Champion with all 127 Available Pokemon
Obtain Lickitung
Obtain Mewtwo after obtaining all 128 Pokemon