Some of Richter's sprites, animations and moves are actually unused sprites from Castlevania: Symphony of the Night, such as his jumping spin kick and crouching sweep kick.
You can play as sisters Stella and Loretta. This mode is a prequel to the main story line. You control the sisters by the directional pad and attack using the touch screen.
By defeating 1,000 Old Axe Armors in the regular story, you can unlock a special version of the game in which you will play as an Old Axe Armor. This mode is the only special mode which does not give you a partner.
Spoiler:Eric Lecarde from Castlevania: Bloodlines appears in Portrait of Ruin as a ghost named Wind. He will give out quests for the player to complete.
There is a special mode called Richter Mode. You play as both Richter Belmont and Maria Renard. Richter plays much as he did in Castlevania: Rondo of Blood, except that he lacks item crashes.
In the hidden portrait, "Nest of Evil", you can fight several bosses from Dawn of Sorrow.