Super Smash Bros. games are renowned for their hidden details and references to Nintendo's rich history. Super Smash Bros. for Wii U is no exception, packed with fun easter eggs and secrets for observant players to discover.

- Hidden Taunts: Some characters have special taunts that only activate on specific stages or against certain opponents. For example, Fox and Falco can perform a 'Star Fox' taunt on Corneria or Venom by pressing down on the D-Pad quickly.
- Palutena's Guidance: When playing as Pit on Palutena's Temple, performing his down taunt (Down-D-Pad) for a few seconds will trigger a unique conversation between Pit, Palutena, and Viridi about the current opponent. There's a unique dialogue for every character!
- Codec Calls: Similar to Palutena's Guidance, Snake (DLC character) has 'Codec Calls' on Shadow Moses Island. While Snake is not in the base Wii U game, this feature was a staple in previous titles and is a common type of Smash Bros. easter egg.
- Mii Fighter Cameos: Your created Mii Fighters can sometimes appear as background characters in certain stages or as opponents in Smash Tour.
- Stage Transformations: Many stages have subtle or dramatic transformations that occur during a match, often referencing events from their respective games. Pay attention to the background!
- Sound Test Secrets: In the 'Vault' -> 'Sound Test' menu, you can listen to all the game's music and sound effects. Some tracks might have hidden messages or unique arrangements.
- Trophy Descriptions: Every trophy has a detailed description that often contains lore, trivia, and humorous references to the character or item's origin game. Reading them all is a secret in itself!
- Master Hand's Hidden Forms: As detailed in the Boss Guides, Master Hand's transformations into Master Core at higher intensities are a secret boss encounter.
Keep an eye out for these subtle nods and hidden interactions. They add a layer of charm and depth to the Smash Bros. universe.