Pokémon Classic walkthrough
10 parts, one per checkpoint Pokémon Classic’s own documentation defines: the areas each one opens, the wild Pokémon and trainers in them, and the fight at the end of it. Everything here is read off the game’s own files, so anything it doesn’t state isn’t claimed.
Part 1: Just started — no badges
7 areas · 17 trainers · Rival, Brock, Rival (Flareon) and 2 more
Part 2: Boulder Badge — Mt. Moon and Cerulean City
10 areas · 49 trainers · Rival, Misty
Part 3: Cascade Badge — Vermilion City and the S.S. Anne
6 areas · 41 trainers · Rival, Lt. Surge
Part 4: Thunder Badge — Rock Tunnel to Celadon City
16 areas · 97 trainers · Erika, Rival (Flareon), Rival (Jolteon) and 2 more
Part 5: Rainbow Badge — the sea routes and Fuchsia City
14 areas · 73 trainers · Koga
Part 6: Soul Badge — Saffron City and Silph Co.
3 areas · 59 trainers · Sabrina, Rival (Flareon), Rival (Jolteon) and 2 more
Part 7: Marsh Badge — the southern sea and Cinnabar Island
15 areas · 53 trainers · Blaine
Part 8: Volcano Badge — back to Viridian City
1 area · 13 trainers · Giovanni
Part 9: Earth Badge — Victory Road and the Pokémon League
7 areas · 49 trainers · Champion (your rival) (Flareon), Champion (your rival) (Jolteon), Champion (your rival) (Vaporeon) and 4 more
Part 10: Champion — the post-game
6 areas · 3 trainers