Defeat your Rival in Professor Oak's House
Defeat your Rival in Route 22
Defeat your Rival in Cerulean City
Defeat your Rival in S.S Anne
Defeat your Rival in Lavender Town Haunter
Defeat Giovanni from Rocket Game Corner in Celadon City
Earn the Boulder Badge in Pewter City
Earn the Cascade Badge in Cerulean City
Earn the Thunder Badge in Vermilion City
Earn the Rainbow Badge in Celadon City
Assemble a full team of Pokemon in your party
Get the Pokemon in Slot 1 from Level 99 to Level 100
Trade Farfetch'D for Flareon in Route 11 House
Trade Butterfree for Tentacool in Vermilion City
Trade Beedrill for Goldeen in Route 5 Underground Path
Trade Spearow for Horsea in Cerulean City
Trade Golbat for Mr.Mime in Route 2 House
Buy Magikarp in Poke Center in Route 3
Go from Route 9 to Lavender Town using the Rock Tunnel and without using Flash.
Obtain HM03 Surf in the Safari Zone
Trade Chansey for Pinsir in Route 18 House
Defeat all Viridian Forest Trainers in a row without leaving the area in Viridian Forest
Earn the Soul Badge in Fuchsia City
Defeat all Nugget Bridge Trainers in a row without moving down in between battles in Route 24
Grab your Fossil and get through Mt. Moon without using any Repel (don't reset)
Defeat all Fighters in a row in Saffron City Gym without leaving the area
Defeat your Rival in Saffron City Silph Co. Building
Defeat Giovanni in Saffron City Silph Co. Building
Earn the Marsh Badge in Saffron City
Earn the Volcano Badge in Cinnabar Island
Defeat all Trainers in Route 21
Trade Kadabra for Alakazam in Cinnabar Island Lab
Trade Raichu for Raichu in Cinnabar Island Lab
Trade Staryu for Dratini in Cinnabar Island Lab
Earn the Earth Badge in Viridian City
Defeat your Rival in Route 22 again
Beat the Elite Four and the Champion of the Pokemon League
Catch 151 Pokemon [Yes, ALL of them]