Ojalá Que Te Mueras (I hope you die) is about as far from a gentle breakup song as you can get. The singer was cheated on, and instead of crying quietly he lists every curse he can think of. The word ojalá (I hope / if only) opens almost every line, and it is the key to the whole song: it comes from Arabic and always takes the subjunctive, so you get "Ojalá que te mueras" (I hope you die) and "Ojalá pagues caro" (I hope you pay dearly).
The curses get very specific. He wants the ground to open, "que se abra la tierra y te hundas en ella" (may the earth open and you sink into it), heaven's doors shut, and thorns stuck in her heart "si es que aún tienes algo" (if you even still have one), which is a nasty little jab. Then comes the honest bit: "Sé que no debo odiarte" (I know I shouldn't hate you), but he can't forget what she did. It is over the top, and that is the fun of it. Also notice acordarte de mí (to remember me): Spanish uses the reflexive acordarse de, which is a handy pattern to learn here.