"Belfast Confetti" opens in media res—in the midst of the action. The verb "suddenly" signals that the poem depicts a frantic and changing situation, and by the first line's caesura, the reader knows that this involves some kind of civil unrest, since a "riot squad" is involved. The alliteration and consonance of /s/ and /k/ sounds throughout the first line and a half gives the opening a chaotic energy:
Suddenly as the riot squad moved in, it was raining exclamation marks,
Nuts, bolts, nails, car-keys.
The sense of immediate chaos in the opening serves one of the poem's main aims: recreating the confusion and fear in the immediate aftermath of a bomb.
But, as is also clear from the beginning, this is not a straightforward literal description of an event. The real-life explosion—the poem is set in the 1960s, during the Troubles in Northern Ireland—is also interpreted and represented through references to language, primarily an extended metaphor comparing the aftermath to punctuation. The fact that it is "raining exclamation marks" as well as the more usual shrapnel found in an improvised bomb sets up the poem's dual focus on violence and language.
The exclamation marks mentioned here work in two ways. First, they carry their usual literal meaning: an alert to danger and a mark of something dramatic happening. But the shape of the mark itself—!—also cleverly represents the bomb itself. This type of bomb has been made fairly crudely and is packed full of any objects that could maim or kill. As the bomb explodes, these objects radiate outwards in fragments—and the exclamation mark, with its separate long line and dot, represents the varied shape of these fragments.
After this more symbolic representation of the bomb, line 2 tells the reader the kind of objects that are actually flying through the air. This moment uses cacophony, deliberately clustering heavy metrical stresses (underlined below) with harsh consonant sounds (in bold):
Nuts, bolts, nails, car-keys.
The lack of conjunctions like "and" (a poetic device called asyndeton) in this list convey the way that these gathered objects were packed tightly into the bomb's casing and adds to the sense that they're densely filling the air.
After line 2's first caesura, the poem uses three more images that develop the link between violence and language. The "fount of broken type" plays with the word "font" (which refers to different typefaces). Throughout, the poem develops the idea that language, though useful, is somewhat unable to capture the true nature of violent experiences like these. So the "broken[ness]" of the "type" in line 2 sets up this anxiety about the inadequacy of language and hints to the reader that even though the poem is trying to describe the speaker's experience, it might fail to do so.