Released in 2023, #0 IGGY'S CASTLE is a horror themed ROM hack of Super Mario World created by Wakana. What appears to be the normal Iggy's Castle is hiding something deep inside it, and Mario is forced to enter it.
This hack contains examples of:
- And Then John Was a Zombie: The hidden ending of the game has Mario becoming the new shopkeeper after killing the original shopkeeper.
- Anti-Frustration Features: Game.bps was harshly criticized for its complete lack of checkpoints. Wakana learned from that mistake by having every room and door transition trigger a checkpoint.
- Art Shift: The Shopkeeper's Realm has more realistic graphics than the SMW graphic edits of the normal castle.
- Bait-and-Switch: The Golden Ending has an initial setup similar to the "Murdered by the Demon" ending, but then Mario can outrun it and escape the castle.
- Deal with the Devil: Selling your soul to the shopkeeper results in Mario turning blue, and makes it much harder to access the Final Boss.
- Demonic Possession: If you sell your soul to the Shopkeeper and defeat the Face Guardian, his soul will possess Mario, locking you into a bad ending.
- Downer Ending: The vast majority of the game's endings are bad endings, with a lot of them involving Mario dying.
- Eldritch Location: The castle itself defies laws of physics, with it getting spookier with each update. In the 2.0 version, flying into the hole you entered from grants access to the Shopkeeper's Realm.
- Golden Ending: The ending that is obtained by buying three items from the Shopkeeper is the best ending, where Mario escapes with his mind, body and soul intact.
- Leitmotif: The Shopkeeper has a leitmotif that starts out 8-bit, and gets more instrumentation the further in the game you progress.
- Multiple Endings: The initial October 2023 release had 5 endings. A later patch added two more endings. Then a third patch released in March 2024 added an additional 6 endings for a total of 13 endings.
- The Many Deaths of You: Some of the bad endings involve Mario being decapitated, slammed into a wall at a high speed, collapsing from extreme pain and being murdered by the demon.
- Nerf: In earlier versions, the Cape is useless because you can't fly with it. In 2.0, the Cape is restored to its vanilla capabilities.
- Point of No Return: This hack has a total of three:
- The first is the Face Guardian boss, which locks you out of different endings depending on whether you spare it by escaping or kill it. If you kill it while soulless, you're locked into a bad ending.
- The second is the door that only opens with the Blood Key, as you cannot go back to buy more items afterwards.
- The third was added in 2.0, and once you fly up the entrance with the Cape and Amulet, you cannot go back to the main castle.
- Rivers of Blood: One of the rooms added in 2.0 features a river of blood.
- Shout-Out:
- Two of the boss themes are from Super Metroid, with Mother Brain's theme being used for the final boss of the original release.
- The use of the Cape and Amulet sends Mario to Otherworld with notable changes in graphics and sound, just like in the Silent Hill games.
- Source Music: During one of the 2.0 update endings, an in-universe organ plays a remix of the Shopkeeper's theme
. - Unending End Card: Once you've found an ending, the only way out is to reset or turn off the console.
- Unintentionally Unwinnable: While playing a prototype, Daizo accidentally softlocked himself in an area that requires being big to proceed by being small and having no way to jump back out. The release version patched this by making the crumble block blocking the door able to be destroyed by Small Mario.
