Brock in Pokemon Yellow. You have no choice of starter, you must use Pikachu. It's the worst situation you could be in as a trainer. Brock has a fully evolved Pokemon (at that time) who is completely immune to you, not resistant as with Charmander but immune. To make matters worse 99% of the Pokemon you've encountered are weak to Brock, it's a forest of flying and bug types. They had to actually change Nidoran's moveset by lowering the level it learned double kick from 43 down to 12, or else there would be no Pokemon anywhere who had a way to deal damage to Brock.
This slither of hope is assuming you already know how to play the game. In-game its your first gym battle, and the first encounter you have with a rock and ground types, yet it presupposes that you know there is poison type out there who would normally be weak to Brock as well, but has a special moveset in this instance that you can level grind to get. If this was your first pokemon game why would you know this?
Wouldn't be simpler to just give Pikachu a super-effective move? Its a special event Pikachu, give it the fighting type move. In the first season of the Anime Ash teaches Pikachu a punching move he invents called rocket punch. It could have been interesting to see that in-game.
Yeah! A lot of what you said is basically how it went down for me. As I chose Charmander, the first 2 gym leaders were the only real struggles. The battle with Brock for me was just done by chipping them down with Charmander and a Pidgey. Misty was also a tad hard, as Pikachu or Bellsprout (depending on the run) aren't very powerful on their own unless I level them up. Which starter did you end up choosing?Misty, I think...
In solely my personal experience, I have only lost to Brock, Misty, and Surge...I consider Brock a beginner's trap, so eliminated him...Surge, while he was my original answer, kinda dies to the fact that you have Ground pokemon all over the place, and they shut Surge down much more effectively than Misty's weaknesses...
Like I said, my personal experience, so I know it's not the most reliable reason to say "Oh these are the only 3 that I lost to"...
Yeah! A lot of what you said is basically how it went down for me. As I chose Charmander, the first 2 gym leaders were the only real struggles. The battle with Brock for me was just done by chipping them down with Charmander and a Pidgey. Misty was also a tad hard, as Pikachu or Bellsprout (depending on the run) aren't very powerful on their own unless I level them up. Which starter did you end up choosing?