I can see why you might think it means "superficial" because of what is written in the paragraph, particularly the last sentence. But that definition doesn't exist for the word 'literal'. 'Literal' means 'being true to its name' or 'true to the actual meaning of the words'. So for example, if I say 'my boss gave me the sack' (which is an idiom), it means I lost my job. But if I say 'my boss literally gave me the sack' it means my boss put a bag in my hands. So in this case, 'literal' refers to the name of the art: 'new genetic art'. I don't know about this style of art, but googling it leads me to understand it as a type of art where the artist's ability 'evolves' like in genetics, using maths and algorithms to make "better" artworks. This might not be an accurate definition, but it doesn't matter. The main thing is that the actual artwork in 'genetic art' does not have to be pictures of actual DNA helices or things related to genetics; 'genetic' refers to the evolution of the artist/artwork or method of creating the art, not the actual image. But, according to your paragraph, the 'NEW genetic art' actually takes the word 'genetic' literally in the images it produces. So that images of DNA for example, are included in or influence the artwork produced. The result of this, according the the writer, is dull and superficial art; but the word 'literal' does not refer to the superficial result; it refers to the new genetic art actually, literally, using imagery related to genetics.

Literal has a few meanings/significations, but here particularly the writer is trying to say that the new genetic artwork is making very direct and logical associations - not a lot of creative or metaphorical thinking. You could say "superficial" but that carries many negative connotations that might not be applicable here. It could be said that the new genetic artwork is only using obvious references, not exploring things further or more deeply in imaginative ways.