So colosseum and Xd are in the spin off section. But I would consider them gen 3 games because they can communicate with R/S/E and FR/LG, you build your own party, level up, explore a new region & clear a story. I think they're more than just a way to get gen 2 pokemon, I think they're there own gen 3 games, and good ones at that.
I always thought of them as gen 3 games rather than spin offs. What about you?
They ARE spin-offs because they don't follow the gameplay as the main games (you know, you start, collect 8 badges, beat league, the routine)
Everything that does not follow this is considered spin-off =)
But yeah, they do belong to 3rd generation gaming.
But they are still spin-offs =D
They are gen 3 games (becausr they were made in that period of time and communicate with RSE/FRLG to boot), but not main gen 3 games.
I'd say the main gen 'number' games are the ones on a handheld, made by Game Freak. While Colosseum and XD do basically use the same game mechanics, they're made on the GCN by a separate company (Genius Sonority), and have their own significant differences (lack of wild Pokémon/no real routes, Shadow Pokémon/snagging, vast majority of battles being doubles). Hence I'd still think of them as spinoffs.
They technically are Gen 3 games. I never really think of them to be related to RSE/FRLG, but that was because I never traded to those games (well only RSE, I don't own Firered or Leafgreen cartridges).