Ener-G Gym Rockets is a simulation game for the Nintendo DS that immerses players in the world of competitive gymnastics. As an aspiring gymnast, the player trains and performs in various gymnastic events, including floor exercises, uneven bars, balance beam, and vault. The game combines rhythm and timing-based gameplay mechanics with a career mode where players can customize their character, learn new skills, and compete to become a top gymnast. It's designed for a younger audience, capturing the thrill and challenge of gymnastics in a fun, interactive format.