This study examines a gamified musical enrichment program using mixed instrumentation and a popular musics-based repertoire with students identified as having high intellectual abilities (HIA) in Spain. Forty-six participants (ages 9–16, M = 12.4) attended six Saturday sessions in Primary (n = 24) and Secondary (n = 22). Conducted in Cáceres, Extremadura, within the TalentiaCC program, the extracurricular setting enabled activities designed to encourage participation, creativity, and engagement in a culturally relevant framework. Data included observation, narrative records, audiovisual materials, and teacher reflections. Reflexive thematic analysis showed that motivation in Primary was linked to playful elements and badges, while in Secondary it was associated with autonomy and leadership. Collaboration was fostered by scaffolded roles, and creativity appeared through rhythmic-timbral variations (Primary) and improvisations with harmonic modifications (Secondary). Five design principles emerged—scaffolded roles, short narrative, moderated collaboration, adaptable repertoire, clear criteria—offering guidance for inclusive music programs and teacher education.