Over half of the album's length is composed of instrumental music, recorded by what was originally a purely free-form jam band.

In a contemporary review for Rolling Stone, Langdon Winner panned Santana as "a masterpiece of hollow techniques" and "a speed freak's delight - fast, pounding, frantic music with no real content".

He compared the music's effect to methedrine, which "gives a high with no meaning", finding Rolie and Santana's playing repetitively unimaginative, amidst a monotony of incompetent rhythms and inconsequential lyrics.

[11] Village Voice critic Robert Christgau shared Winner's sentiment in his "unreconstructed opposition to the methedrine school of American music.

[10] A retrospective Rolling Stone review was more enthusiastic, finding Santana "thrilling ... with ambition, soul and absolute conviction - every moment played straight from the heart".