I beat Pokémon Card GB2 after
getting an English patched version of the game.
Although the latter half of the game introduces "special rules" like Fire-only energy cards and have 4 of a certain type of card in a deck; A few Articuno lv 35's with Full Heals, Potions, Super potions and a fuckload of Water Energies is
still all it takes to win most of the game.
I also
made a map for a labyrinth in the GR fighting fort. I suck at labyrinth puzzles, so it helped a lot.