What are the uses of the three special crystals in castlevania for Nintendo 64?

Answer 1

There are three special crystals total in Castlevania 64 but you can only get 2 at a time with any character. Holding special gem 1 in the Forest of Silence unlocks hard mode for that file when you beat the game, holding special gem 2 (Reinhardt only) in the Tower of Execution unlocks Reinhardt's alternate costume once you beat the game and hold up on the analog stick when selecting Reinhardt when starting the game on that file again, and holding special gem 3 (Carrie only) in the Tower of Sorcery unlocks Carrie's alternate costume once you beat the game and hold up on the analog stick when selecting Carrie when starting the game on that file again.

Also keep in mind that the remake of this game (Legacy of Darkness) does not have any special gems so don't waste time looking for them. Instead, these things and more are unlocked upon fully completing Henry's game mode.

Answer 2

The green one called Special 1 will unlock Hard Mode, the red one called Special 2 will unlock an extra costume for the character you obtain it with. There are also white ones scattered acrossed the levels, these crystals are save points. To save you will need the Controller Pak accessory attached to the back of your controller, then approach the white crystal and press C Right and say Yes to save data.