Well i recently BOUGHT Pokemon Firered. To begin with Pokemon... And i have a few questions:
- Is it handy to train more pokemons at the begin?
This has already been covered, but I will repeat it. It is not handy to train multiple Pokemon in the beginning, unless you like wasting time battling low-level Pokemon that don't yield many Exp points.
- Is Pikachu good? (Yes i wanna know, i thought it was rare or something)
Contrary to what others have said, while Pikachu is a serviceable Electric-type, it is definitely not the second-best Electric in FRLG. Jolteon, Electabuzz, and Magneton are better options. The first two are superior to Raichu (and especially Pikachu) in every statistical category except Atk, which doesn't matter much on an Electric-type. While Magneton has less HP and Spd, its 25 bp higher in SAtk more than make up for it. All three also have more diverse movepools to choose from.
- Does this pokemon game has any other generations in it?
Depends on your definition of "generations". You are able to catch some wild Johto Pokemon on Sevii, but that is about it. Between FireRed and Emerald, you should be able to get all but a handful of Pokemon (Event Legendaries excluded).
Thanks.