It was for the GBC/GBO... So it is only the original run of cards... Original Pokémon. Probably only a few hours long if you hardcore it and get lucky with the cards in the booster packs etc.
Hitmonchan is amazing. 70 HP, 20 damage for 1 energy and 40 for 3. Psychic decks are pretty rare too so you don't have to worry so much about getting bashed for double damage that often.Right now I'm pretty sure Hitmonchan is just the total boss of this game, and once you get one of these guys set up you're basically guaranteed to win.