Tropes this work include:
- Downer Ending: Is to be expected.
- Dream Sequence
- Foregone Conclusion: Castel admits killing Maria in the first chapter, the book is about the situations that led to this. Surprisingly, the end is equally traumatic even if (or perhaps because) you know.
- Genre Blindness: Even if you didn't know the ending because Juan Pablo told you every single freaking thing he does screams of "Woman Murdered by Stalker" headlines. Maria probably knew in the bottom but still...
- Hikiko Mori: Castel hardly leaves his place before meeting Maria. This is never shown to be weird, possibly as a reference to society's willingness to forgive weird behaviour in famous artists.
- Insane Troll Logic: Castel shows instances of this, particularly when he compares Maria with a hooker.
- Ironic Echo: Everywhere, which only makes it worse.
- Meaningful Title: The Tunnel represents Juan Pablo's eternally lonely existence, which is like a dark tunnel where only he stands. He sometimes sees through windows in the tunnel, and even once sees a fellow traveler in her own tunnel, but the walls will never fall.
- Oh, and X Dies
- Rich Bitch: Mimi.
- Stalking Is Love: Maria falls for the Stalker With a Crush. Which leads us to...
- Stalker With a Crush: Juan Pablo is absolutely insane, instantly fell for Maria in a matter of seconds and then proceed to live forever obsessed with her, eventually killing her out of jealousy.
- Shout-Out: Castel is partially based on the Spanish painter Oscar Dominguez, who appears in other works by the author. His insanity attacks and physical appearance (which isn't described until his cameo on another book of Sabato) is pretty much Dominguez.
- Unreliable Narrator
- Up to Eleven: And you thought Neon Genesis Evangelion was depressing...
- Woobie, Destroyer of Worlds: It is hard to hate Castel when you realize how majestically insane he is.
Did we mention yet that True Art Is Angsty?