1. 2nd gen - I really like this generation. It was the first sequel, telling us that the game series will continue. Introduced a lot of new features. Had 2 great starters and made me like zubat ugh Also the inclusion of Kanto in the postgame was genius, it was very nice to see familiar characters/places. And to top it all, that final battle against red (spoiler alert) was just perfect, even the dialogue was awesome Besides, I didn't have access to the internet, so I had to do all the exploration by myself, I still remember the ruins of alph very fondly.
I'm also counting SS and HG here, so being able to walk with my legends/starter behind me was really nice!
2. 1st gen (Kanto) - It has 3 great starters, venusaur being my all-time favourite, and a lot of my favourite pokemons like gengar, alakazam, ninetales, snorlax, etc. The first time that I played it I didn't even speak english So it was cool to replay the game several years after that and finally understand what is going on. Poor marowak I liked the story, enjoyed the inclusion of Jessie and James and the league was a real challenge.
Gen 1 was not balanced and that added to the difficulty, Terra's glitch field can attest to that So that finally battle against Mewtwo was crazy, He was the strongest pokemon, with a type with no real weaknesses and a moveset to really annoy the player Good luck catching it if you didn't save your masterball. So far, for me, it was the hardest challenge in any pokemon game.
3. 4th gen (Sinnoh) - I really only like one starter, chimchar, but can understand the appeal of the other 2 It has lucario, garchomp, staraptor, luxray and best of them all bibarel! It wasn't a hard game but I enjoyed the story and their characters, Cynthia is the best champion in all generations! It also has the best introduction of a legendary with Giratina and a very cool distortion world to explore.
4. 7th gen (Alola) - I like all 3 of the starters and most of the new mons. The story was ok but nothing special. They renewed the formula by removing gyms and adding trials and It worked. I really enjoyed the silliness of team Skull and the absurdly-OP Ultra Necrozma I was not counting on that one, when it appeared in the wormhole... But still, too many unsinkable cutscenes!
5. 5th gen (Unova) - It has one great starter in serperior, one meh starter in emboar and an abomination in samurott (Dewott deserved better!). It has a lot of cool mons. The story was engaging, specially the sequel, and I liked the rival, N not cheren or the other one. I also like Hugh in the sequel but he made me feel guilty about the name I gave to him Ghetis was a nice challenge but he was the only one, the rest of the game was kinda easy.
2. 3rd gen (Hoenn)- I like this game, Its so low in this list because the other games are really good It had the best trio of starters of all the games, a lot of new cool pokemons and features. The story was pretty straightforward , I liked the cutscene with the 3 legends and the puzzles for the regis.
BUT, I always felt that the motivation between the evil teams was really stupid, it also started the annoying trend of not having asshole rivals (Again, sorry Hugh) and I really didn't like the endless water routes
3. 6th gen (Kalos) - How can a game be this easy?