Castlevania: Bloodlines offers some hidden features and difficulty settings that can alter your gameplay experience.

- Difficulty Settings: The game typically starts on Normal difficulty. After completing the game, you might unlock a Hard mode, which features stronger enemies, fewer item drops, and more challenging boss patterns. Some versions also have an Easy mode, which makes the game more forgiving.
- Sound Test: On the title screen, there's often a hidden input (e.g., holding certain buttons and pressing Start) that unlocks a Sound Test mode, allowing you to listen to the game's excellent soundtrack.
- Continue Codes: While not a 'mode,' the game uses a password system for continues. Learning how to generate or find these codes can help you pick up where you left off without starting from scratch.
- Character Swap Glitch (Specific Versions): In some early versions of the game, there was a known glitch that allowed players to swap characters mid-game under very specific circumstances. This is not an intended feature and is generally not recommended for a standard playthrough.
Exploring these options can add replayability and new challenges for seasoned players. Always check the game's manual or online resources for specific button inputs for hidden features.