The Pokémon Gym Leader Simulator (GymSim) fan project challenges players to act as a defensive authority within the Gym Leader Association rather than a traditional challenger. Recent updates as of April 2026 have enhanced gameplay by adding over 150 unique challengers, a new signature move tutoring system, and over 290 starter options. Watch a detailed overview of the gameplay mechanics and updates at
—a move you "accidentally" left an opening for—the impact shatters your defense. The Aftermath pokemon gym leader simulator upd
Let’s be real: The old puzzle system (just lining up ice tiles) was weak. You wanted Cruelty. You got it. The Pokémon Gym Leader Simulator (GymSim) fan project
— Dev Team @ GLS Studio