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I chose the Blue Version because its exclusive Pokémon are more powerful. As for the starter, I think Squirtle is the best option if you want to keep it in your team forever: it only has 2 weaknesses, it has a very decent defense stat, you can take advantage of Wartortle's EV yield to raise its defense even more, and Blastoise will have the higher defense stat out of the three starters. You can also turn it in a very powerful offensive Pokémon by teaching it Ground- and Ice-type attacking moves.
In Pallet Town I received a Squirtle from Professor Oak, and I immediately defeated my rival, Blue, who chose Bulbasaur. I didn't progress much in Route 1 before training Squirtle up to level 8 so it learns Bubble.
After quickly visiting Viridian City, going back to Pallet, getting the Pokédex from Oak, and returning to the city, I went west to Route 22, where I defeated Blue again right after training Squirtle up to level 15 so it learns Water Gun. I didn't catch any new Pokémon in order to get free Poké Balls from Oak. I already wanted to continue with my journey!
I caught every Pokémon in my way and then spent some time in Viridian Forest training most of them, taking care of move types and EV yield. For example, Pidgey was trained without evolving up to level 28 so it learns Wing Attack, and Weedle was evolved at level 7 but then it was not evolved until level 19 to take advantage of the increasing defense stat thanks to Kakuna's effort values. After my training, I passed through the forest, defeating every trainer in my path.
Finally, I arrived into Pewter City. All I did in here was challenging its Gym, and after defeating the trainer before Brock my Squirtle evolved into Wartortle, so you can imagine that the whole challenge was actually a pretty easy fight. This was my team when I earned the Boulder Badge:
Route 3 was full of trainers, but it was nothing to worry about.
Mt. Moon, a three floor maze, was a lot of fun! That it where I caught and evolved Clefairy. I also met the Team Rocket with their strong Pokémon, but I managed to survive without returning to the Pokémon Center. At the end of the maze I chose the Dome Fossil just because Kabutops is a little bit stronger than Omastar.
There is nothing much to see at Route 4, but it is where I trained Pikachu before challenging the Cerulean Gym.
Finally, I arrived into Cerulean City. All I did in here was challenging its Gym. Its trainers were not an actual challenge, but Misty was stronger, although my Pikachu and Beedrill were powerful enough to defeat her. This was my team when I earned the Cascade Badge:
Before leaving to Route 24, Blue showed up. He was making fun of me, like he always does, but I deafeated him without any problem. The hard training is really paying off. Traveling to meet Bill was actually very fun, even with the many trainers in the Routes. I went back to Cerulean City and defeated the Rocket burglar. Then I left a Magikarp and a Meowth at the Pokémon Day Care --- I do not intend to train them, so I just left them in there to evolve them.
I eventually reached Vermilion City. I went on board the S.S. Anne and defeated every single trainer, including Blue. It was not very hard, and it was a good place to train Bellsprout.
Challenging the Vermilion Gym was very fun, especially because I was using Wartortle with the Dig move against Electric-type Pokémon. It was just a matter of healing after every battle. I was little afraid of loosing against Lt. Surge's Raichu, but I survived somehow. This was my team when I earned the Thunder Badge:
After defeating Lt. Surge, my journey became a series of small adventures. I challenged many trainers and caught some new Pokémon, I travelled through Digglet's Cave and went back to familiar places, until I finally reached the Rock Tunnel.
I spent a few minutes in there to catch and train a Machop. Passing through this tunnel was quite difficult because of the many trainers in there, but with some Potions and Ethers I was able to find the exit. And there were more trainers after the exit! But it wasn't any harder than the tunnel itself, and I got to see that Pokémon Tower in Lavender Town. I immediately left Lavender to the west, training in my way to Celadon City.
In Celadon City there is a free Eevee. I really wanted to train Eevee, but I found that it would unbalance my team. Anyway, I carried on, evolved some of my Pokémon with the evolutary stones, and challenged the Celadon Gym.
The Celadon Gym was the easiest so far. I never needed to heal my team, and Hypno and Beedrill were powerful enough to defeat every other Pokémon with one or two moves. This was my team when I earned the Rainbow Badge:
And now that I am at Celadon City, I found the secret Rocket Hideout. It was very simple for my very well trained Pokémon. Not even Giovanni was a real danger to my team. In fact, I was more worried in gaining money in order to reclaim some prizes at the Rocket Game Corner.
After that I travelled all the way back to the Pokémon Tower in Lavender Town. Blue was waiting for me in there, but the coward left after I deafeated him. At the top of the tower, after fighting Ghost-type Pokémon and many possessed trainers, I rescued Mr. Fuji from the Rocket Team.
I gained access to Saffron City. So, after meeting Mr. Psychic, I challenged the Fighting Dojo. My recently adquired Gastly learnt the Psychic move, so it was a very straight forward challenge. After winning every battle, I picked Hitmonlee as reward after defeating every trainer in the Dojo.
Without leaving the city, I found out about Silph Co., and it was temporary controlled by the Rocket Team. This was the opportunity to test my team. However, I was worried only for a couple of times when Beedrill was almost defeated by a few Psychic-type Pokémon. It is really hard to train Beedrill since it needs to level up a lot to be able to match against strong Pyschic-type Pokémon, specially when Psychic moves are effective against it. However, not even Blue or Giovanni were a real threat, and I liberated Silph Co. and earned the only Master Ball in the game.
Well, because Beedrill is not as defensive enough and because it is weak against Psychic moves, the Saffron Gym became too hard at the end. The trainers in there were not as hard as the Gym Leader, but Sabrina tested the best of me. After a few tries, I was able to defeat her almost by chance. At this point I realized that it might be better to have trained a Jolteon and use it to replace Beedrill, but it is too late now. This was my team when I earned the Marsh Badge:
Travelling from Saffron to Fuchsia City was a lot of fun. I passed through Celadon, using my bike the whole time, meeting a lot of tough trainers in my way, and catching one of the two Snorlax found in Kanto! And, in Fuchsia I got a new fishing rod to help me complete my Pokédex.
In Fuchsia City, the first thing I saw was its Gym. So, after fishing a couple of Pokémon, I challenged the Fuchsia Gym. And once again my starter Pokémon has an effective move against the Gym Leader. I feared for my Beedrill, which I had to heal a few times, but I was able to defeat all the trainers easily. Koga, however, was an easy and fast battle. This was my team when I earned the Soul Badge:
The Safari Zone is a lot of fun! The Pokémon in here are very hard to catch, but I finally got a Tauros and a Rhyhorn. I didn't find the rare Chansey, but I will try catch it later in the game.
Since I have not teach Fly to any Pokémon yet, I ride my bike all the way back to Celadon City, and then to Lavender Town, from where I travelled south via some unknown routes, catching and fishing a lot of new Pokémon.
Back in Fuchsia City I taught Surf to my Dratini, and that I was able to reach to the Seafom Islands, not before meeting a lot of trainers. In this islands I spent a lot of time catching every single Pokémon I did not have, and at the end of the dungeon I met the legendary Articuno. I didn't spend a lot of time against it because I simply caught it with the Master Ball.
Then I surfed to the hot Cinnabar Island. I unravelled the misteries of the Pokémon Mansion while I trained my team and caught many new Pokémon. At the bottom floor of the Mansion I found a Secret Key that granted me access to the Cinnabar Gym.
I obviously had the advantage in Cinnabar Gym. In here, my starter quickly evolved into Blastoise, which allowed to teach it new moves that I was keeping in the form of TMs. However, my Dragonair and my Rhyhorn were sufficient to beat every trainer and Blaine, the Gym Leader himself. This was my team when I earned the Volcano Badge:
After defeating Blaine, I travelled across Kanto to meet new trainers and to catch more Pokémon, and even trading a Poliwhirl for the rare Jynx. This time there wasn't any new addition to my team.
I have one legendary Pokémon, and I must have another! I went west, to the Power Plant, where many Electric-type Pokémon are roaming the ruins. Despite being weak against Electric-type moves, my Blastoise was able to handle the Pokémon in there, and defeated almost all of them with its Earthquake move. I even used this move against Zapdos twice, making it weak enough to catch it.
Viridian Gym didn't require much effort, specially when I had the advantage since I chose my starter. And, to be honest, Giovanni was easier to defeat than what I expected. In the other hand, I had a lot of effective moves, so I will not say that normally this is an easy Gym. This was my team when I earned the Earth Badge:
Elite Four and Champion
The way to Victory Road was a long way, not because its length but because its powerful Pokémon. From this part of the game, all I'll meet will be the strongest Pokémon in Kanto.
The Victory Road was full of fun puzzles, but I had a hard time passing through this maze. The trainers in there are indeed worthy of being in there, hoping to challenge the Elite Four, just like I will. Almost at the end of this long maze, I was able to catch the last legendary bird and add it to my team. I sincerely hope that all my training will make a difference when I challenge the Pokémon League.
The Elite Four wasn't very hard, since I had the required effective moves. However, Lance had very strong Pokémon, so it took some time to defeat him. Fortunately, Blastoise was strong enough to defeat his Dragons with the Blizzard move. After him, I challenged the Champion, which turned out to be Blue. Only his Gyarados was a real treat, and I defeated all of his Pokémon with Blastoise, except for his Venusaur, against which I used Moltres. Moltres was not only defensive against Venusaur's Grass-type move, but it had learned a very strong Flying-type move that defeated its opponent in one setting. This was my team when I entered the Hall of Fame:
Adventuring through the Cerulean Cave was a bit hard because of its very powerful Pokémon, but I was able to find Mewtwo without much trouble. Its Recover move was very annoying, but I blasted it mostly with my Blastoise's Hyper Beam move. When it was really weak, it was almost a matter of chance, so I shoot a Ultra Ball while crossing my fingers. I almost fell off my chair when I saw that Mewtwo was caught after one try only. This was my team when I caught Mewtwo: