Castlevania: Portrait of Ruin

Bosses

The final four bosses faced before being able to fight Dracula are Medusa, Frankenstein's Monster, the Mummy, and The Wolfman. This marks the only time in the series that all five of the "classic movie monster" enemies have full boss character status.

Sleep mode

When closing the cover of the DS to enter sleep mode (with the game still powered on), the game will make a sound effect simulating a coffin closing shut.

Stella

When battling Stella, one can hear her pronouncing the name of an attack sounding like "Secret Surious Wave". These actually are two overlapping samples, "Secret Strike" and "Furious Wave" (the original Japanese samples were much shorter, and didn't overlap). The simplest way to hear "Secret Strike" alone is by pressing "Start" during the word "Secret". The game will open the menu, but the sample will play to the end. When the menu is closed, Stella will say "Furious Wave".

Information also contributed by Chentzilla and Lain Crowley.