Old Castle Street is the version of Castle Street from the first few incarnations of the Litle P and Sandslash Series, based in particular off of the Super Mario Bros. and Super Mario Bros. 3 stories. It most recently appears in Fantendo Hearts as a level.
This world is ruled by an older, more "royal" version of Princess Cleffa. It is constantly saved by The Little Pikachu and Old Sandslash.
In Fantendo Hearts, it appears as a small world, comprised of 5 different areas. Cleffa's Castle, Plains, Underground, Water, and Blastoise's Castle. The level itself takes place after the events of the series, as Blastoise and his minions are nowhere to be seen.
In the story, you must traverse this level to get to Blastoise's Castle, which has been renamed and reclaimed as Gengar's Castle. Everybody in this world is portrayed as monchrome for unknown reasons.
- Old Sandslash is noticably darker in shade and larger than modern Sandslash. This is probably only to make them look different, though.
- In reference to the original stories, The Little Pikachu and Old Sandslash only talk by jumping, which only Old Princess Cleffa can translate.