Although he wrote both instrumental and vocal music, he is better known for his innovative instrumental compositions. He contributed to the early development of the string idiom by expanding the performance range of the solo and accompanied violin and incorporating slur, double and even triple stopping, and the first explicitly notated tremolo effects into his music. He was also among the first composers, after Marco Uccellini, to call for scordatura tunings. He made contributions to most of the contemporary genres and investigated unusual compositional procedures, like constructing an entire sonata without a cadence (as in his Sonata senza cadenza). At least some, and perhaps a great deal, of his output is lost, but that which survives exhibits his inventiveness, lyrical skill, harmonic boldness, and growing tendency toward common practice tonality. In addition to his violin works, he wrote music for the cornet, bassoon, and trombone.
One latter-day champion of Marini's music is the British violinist Andrew Manze, who has released a disc on the Harmonia Mundi label entitled Curiose e moderne inventioni devoted to Marini's music for strings.