What was your best achivement in GSC?
And what was your hardest achivement?

Mine was a Lvl 100 .

Probably that I have like 20 lvl 100s and that I have around 200 in my pokedex which is the closest ive come to completing a pokedex.

Right now I have 8 lvl 100s on 64 hours of gameplay. Feraligatr, Houndoom, Tyranitar, Gengar, Machamp, Zapdos, Mewtwo, and Aerodactyl.
I'm now working on Snorlax, Kingdra, possibly Dragonite, an as of yet unknown Grass-type, and definitely the Pokedex. I plan to get all 250 (not counting Celebi) without using Gameshark/Brainboy (without which I cannot get Celebi).

Getting a Slowbro, Meganium, and Kangaskhan all to level 75. They were the best Pokémon I ever had.

i think my greatest um... thing is that i beat the pokemon league with 3 pokemon.

A typhlosion lvl 50

Ampharos lvl 53

and a Nidoking lvl 51

yay me!!

Raising both my Lugia and Ho-oh to L 100 as well beating Red in one fell swoop. and capturing the three beasts

I remember raising a pair of bred Larvitar to 100, male and female. That took forever. I stopped playing Gold after that

Beating the game was tough for me. But it was still really fun.

Well mine is getting all 3 legendary dogs with ultra ball and I have NEVER use my master ball .

Beating the game, and beating the Kanto gym leaders.

Another was just being able fight Red.

Beating Red with a level 100 Dragonite.

I loved hatching shiny pokes from that goldenrod daycare.

my greatest achievement in that is having my whole party as lvl 100, having around 6-8 shinies I think, and catching around 200 guys.

I think it was when I caught and when I finally reached lvl 100 with it.
Unfortunately my Crystal game doesn't work anymore So I haven't got the lvl 100

Probably beating the lvl 129 Vileplume/Octillery in the Celadon city gym

Anyone know what I'm talking about?

I googled it for like half an hour and couldn't come up with it. So it's time to swallow my pride.

How did you find a level 129 Vileplume/Octillery in the Celadon Gym?

Before Gold/Silver was released in Europe (I don't know about the US), you could download a fan translation of the Japanese games (a rom). It was very glitchy, and crashed whenever a foe used Protect or Detect, and whenever a wild pokemon fled. Also, in Celadon gym you would face a L4 Rattata, then a L127 or L129 (can't remember) Octillery with a Vileplume moveset. It was quite tricky to beat, until I learned the ways of Wobbuffet...

My biggest achievement was getting my team to level 100. Had a Feraligatr, Lugia, Houndoom, Scizor, Tyranitar and a Raikou. Was hard going levelling them all up to Level 100, but, it was a good team. Then my brother deleted the game.

Lot's of Bug Catchers on this topic

Haven't played Crystal for too long, so I don't really have any signifigant achievements. I did manage to get my Togepi to use Fissure twice AND hit both times using Metronome. lol poor Ratatta

Would have to be the starter. Back when I played that way, I had a Lv. 79 Meganium (I know, it's not 100...). Then I traded it to my brother. Eventually, he grew it to Lv. 85, but the internal battery died after that...

So I lost everything I had. I was also proud of my Pidgeot. (It was the first time I had gotten one...)

AEPMT

finding out my starter was shiny
getting a lvl 100 shiny tyranitar
getting all badges in both regions

My level 46 beat Lance's Gyarados and two Dragonites in succession without me using any items. One HP left, too! Woohoo!

Breeding a shiny dratini(red gyrados helps).

Winning the lottery only having two different ID numbers.

Either beating the E4 with just Lugia or else beating Ash/Red with a team at average Lvl45.

Oh, and probably when I completed the dex almost a decade ago, that includes Mew and Celebi.

that was the last dex i completed too