A "randomizer" isn't a new game. It is a patch or a pre-patched ROM that scrambles the game's data. When you boot up a randomized Emerald, the game logic stays the same (you still need 8 badges and to stop Kyogre and Groudon), but the contents change.
The is the ultimate way to revisit Hoenn. It strips away the meta-knowledge and forces you to play with your gut instinct. You will use Pokémon you’ve never looked at twice because they are suddenly the only thing that can survive the third gym’s Mewtwo. pokemon emerald randomizer rom
For the uninitiated, a Randomizer ROM is a modified version of a classic Pokémon game, in this case, Pokémon Emerald, with randomized elements that alter the player's experience. These modifications can range from randomized Pokémon encounters, altered type matchups, and changed item distributions, to more extensive changes like shuffled Pokémon locations, abilities, and even starter Pokémon. A "randomizer" isn't a new game