Actually, every move I used was Super Effective against his pokemon.

Low Kick, although awesome against Snorlax, wouldn't be as effective against Lapras, because of the much lower weight. Feraligatr's Superpower works best. 

But you pitched Feraligator against Pikachu. Which worked, obviously, but was severely damaged.

How did Hail get into the equation anyway? Does Lapras have it?

Nice job Letsatdark! Here's what I did (I think...)

Pikachu: Gliscor (Used Stealth Rock, then used Earthquake. He soaked up Iron Tail like a champ!)
Lapras: Electivire (25% Stealth Rock Damage then used Thunderbolt)
Snorlax: Scizor (Shrugged off Snorlax's attacks and took him down with a couple of Bug Bites)
Charizard: Feraligatr (Took 50% from Stealth Rock and Waterfall did the rest)
Venasaur: Magmortar (Fire Blast did the talking)
Blastoise: Electivire/Weavile (Electivire did some damage... but not enough to finish the job and sacrificed himself to save the world from... er... he just fainted. Weavile stepped in and finished the job with Night Slash)

It's a constant effect due to the weather in the top of Mt. Silver

I was working on the Battle Frontier to get Earthquake for my Electivire, but I recieved a Focus Sash through Mother's phone-calls, so that launched me to fight him.

@Smeags

Thanks man

That was a pretty good strategy you used there  

I never got to use either Dragonite nor Scizor, pretty much Electivire, Charizard and Feraligatr were all that I needed, due to their versatility in moveset xD

Congrats, now time for you to go Legendary hunting. Shouldn't be hard, but I think there are more Legendary Pokemon in this game than any other game...

Raikou,
Entei,
Suicune,
Lugia,
Ho-Oh,
Zapdos,
Moltres,
Articuno,
Mewtwo,
Groudon/Kyogre(depending on the version),
Latios/Latias(depending on the version),
Dialga/Palkia/Giratina(no idea how you do it but you get to choose one of them, they start at lvl 1)

Bring lots of Ultra Balls!

And don't forget to get your Kanto starter from Prof. Oak in Pallet Town, and Hoenn starter from Steven Stone in the Silph Co. building in Saffron City.

I've go pretty much all of them except the version exclusives (Latias and Kyogre, which in consequence doesn't allow me to get Rayquaza) and the Dragon Trio from D/P/Pt

To get the Dragon Trio, you'll have to trade an Event Arceus to Heart Gold/Soul Silver and then go to the Ruins of Alph. In there you'll find Cynthia, whom will take you to the Sinjoh Ruins. Arceus will create one egg from one of the Dragon Trio, but it will be one chance only. Since there are two Event Arceus, in theory, you can get two of the Dragon Trio.