"flash and dot" are used here as verbs, not nouns.
"truncations" is the final noun in a list of 4, all of which are the subjects of "flash and dot".
A "truncation" is a sudden shortening. So if I started a sentence and then...... I've just given you an example of a truncated sentence.
"flash and dot" mean that the text is full of these textual features which the writer is critical of, in the case of this particular writer.