To obtain the hard difficulty setting you must get the first green jewel. That will release "Secret #1" on the Item List. It is located in the forest stage in a torch upon a floating platform.
Once you've done that, finish the game with either character. After the ending sequences and credits, you will be able to save your game and select a new, previously unaccessible HARD difficulty mode.
Hidden Powerup in Drac's Lair
When you are climbing the stairs up towards Draculas Lair, you pass through two towers before reaching the final tower. At the last tower, jump onto either of the two torches and slide around the ledge to the other side. There you will find a breakable torch with a Red Jewel and a floating platform. You can walk to the platform on thin air by walking straight toward it from the torch with the Red Jewel. Inside you will find a Healing Kit, helpful for the major battle(s) to come.
Reinhardt's Second Costume
In the Tower of Execution, go up to the third level and slash one of the Iron Maidens to get the execution key. Now jump back down to Level 2 and enter the Iron Gate that was once locked. Walk down the hallway and look over the ledge to see a floating platform with an iron maiden. Slash it to reveal the purple jewel which is secret #2 on the item list. This will unlock Reinhardt's 2nd costume.
Secret Items in the Castle Courtyard
In the Castle Courtyard wait until 12:00 midnight and a secret platform will rise from the fountain allowing access to the items on the top.
Secret of Charlie Vincent
In the Villa, Charlie tells you he is off to defeat Dracula with or without you. During the rest of the game, if you use too many sun and moon cards, i.e. take too many days to reach the final stage, Charlie will have arrived before you and been bitten by Dracula's servant. Charlie will become a vampire you have to kill. This determines the good or bad endings. Fight Charlie and you see the bad ending. But if you get through the game swift enough to arrive at Dracula's servant before Charlie, you get to fight the "true" forms of Dracula and see the good ending.
Secret of Renon's Contract
In the Villa Stage, Renon tells you there is a part of his contract that you cannot read. What it actually says is that you can visit Renon as often as you like, but your total purchase of his items cannot exceed 30,000 gold for the rest of the game. If you do spend over that amount then Renon will fight you.
Talk to Rosa
To talk to Rosa, a vampire who waters the roses in the villa, enter the room with all the red roses in it. At 3:00 A.M., Rosa will come and water the roses.
