Complex sentence: "1 +1" showcases Knowles' vocal-flexing over "magnificent guitar bombast", whereas "Start Over"--which features huge vocals--is a song set against a dramatic and futuristic beat with electric elements.
Split into simpler sentences: 1 +1 was seen to showcase Knowles' vocal-flexing over "magnificent guitar bombast". Similarly highlighting her voice, "Start Over" is a song set against a dramatic and futuristic beat with electric elements.