Yes punish my heaven. The song has a very mellow and powerfull ending which is full of sentiment. It might not seem "slow" if you take a metronome to it but when compared to the frantic pace of the rest of the song its very slow.
In fact the entire song is build around this slow mellow breakdown: The song opens with a fast frantic melody designed to exite you and get your atention, then the song proceeds to do a series of elaborate really fast riffs that keep building tension. But as you might know the best way to build tension is not to try to push the listener as fast as you can, its better to adquire momentum so the song slow downs on its chorus. Immediatly after this chorus the song abruptively ends to create an anticlimatic touch that grabs your atention and resumes the incredible stream of frantic melodies and harmonies flying chaotically through your speakers, then we hear a small fast guitar melody followed by a very emotive chorus acompanied with contrasting levels of guitar melody harmonizing each other with the frase "if i had wings would i be forgiving? If i had horns, would there be flames to shy my smile!!"
The song repeats this powerfull theme again using the pull and release approach to building tension on a song, then it slows down to present is chorus again with an incredible smart touch of irony screamed in the lyrics creating an "anti chorus" luring us into a false sense of security when we know things will go wrong, which prepares you to whats comming when the song finally slows down, we hear this incredible dramatic voice that shines through the song thanks to the very smart use of clean vocals.
So now we are on the main part of the song, it shows us the lead guitar playing carefully crafted melodies more interested in transmiting a sorrow feeling instead of creating ambient and tension like on the previous part of the song because this is the main part of the song, we continue to hear the song and now we arrive at what is the main part of the plot on the lyrics when the end unfolds infront his eyes, they proceed to show you the emotional impact of this tragic events like every good drama taking its time to carefully craft this special moment of deep sadness and emotion that lies on top of the skin until we reach its climax and the song ends.
So this song is dark tranquillity making the ultimate ballad, they slowly build up and create a lenghty intro which plays like a minisong just so the main part of the song, the mellow part, is more easily appreciated and more valued giving a much better climax than any of your typical boring ballads which just start in the middle of the story all sad and slow.
But yeah, I think I could be more specific. When someone says the word "ballad" and its connected with a metal band, the first thing that comes to my mind are those cheesy speed and power metal ballads. But then, in general, I would say the only thing that makes a song a ballad in my eyes is the fact that its slower (or slow) and a bit melancholy (with the exception of all doom metal songs, of course 
