In between the Garden and the Chapel is a vertical staircase going down. On the right hand side of the staircase is a golden statue bearing the number 777. In order to get past this statue, the last three digits of your gold amount must be 777. The statue will move, giving you access to a room with the 'Three 7s' clothing, which boosts your Con., Int., and Luck by 7 points each.
To obtain this, go to the left of the Condemned Tower, then down after the Harpy pathway. In this area, there will be a lot of Medusa Heads. If you fall on the right side, you'll find a slot machine with the number "573" on it. The slot machine will spin to the last three digits of your gold count (if you have 1,945 gold, it'll spin to 945, etc.) If your last three gold digits are "573", then the slot machine will slowly move out of your way. If you don't have your last digits at "573", go to The Lost Village. All the lampposts you can break, especially the one in Hammer's Shop, are great for collecting money. Blue coins give $1, Bronze give $10, Silver give $50, and Gold give $100. Make sure you know the coin amounts, since the procedure is pretty important.
After you get "573" as the last digits, go back to the slot machine. It'll erode away, and inside will be the Shaman Ring. It increases EXP gain which is pretty useful when you want to level faster.
Crown: In Demon Quest House is a room where is a chair and a Skeleton waiter. Sit on the chair in that room and the crown will appear middle of the room.
Bell: In The Dark Chapel is a room with imps and 3 big bells. you need Hippogryph soul to get the bell. Jump with the Hippogryph souls power (up + L) to hit under the bells. try doing it on all the bells. if you hit the right one a bell will drop down from the bell.
Konami Man: In the spike maze Tanjelly room in the Clocktower, kneel on the unspiked top area and he will fly towards you.
Get up close to a wall. Activate the Succubus soul. Before the animation ends, use a dagger special attack. It needs to be the backstab move. After you do the special, do three normal attacks with the dagger and then do the special again. You will be teleported a few squares forward.
Insert the Castlevania: Aria of Sorrow GBA cartridge into the GBA slot before turning on the game. Then go to Yoko's shop and you will see a Mina doll in the background waving her arms.
In the left part of subterranian hell, there is a slot machine door, make sure your last 3 digits of your gold are 666, the door will slide back, and you can get the gold ring, making monsters/candle drop more money!
Collect all souls to unlock the chaos ring. It will appear in one of the blue rooms of the abyss. It gives the user extreme MP regeneration (practically infinite) and a stat boost.
Worst Ending: During the second battle with Dario Bossi, simply beat Dario.
Bad Ending: During the second battle with Dario Bossi, use the Paranoia soul to enter the mirror. After you beat the new boss, Aguni, go back to the other side of the mirror and get the magic seal. Go to the center of the castle and enter the boss door without Mina's tailsman equipped.
Best Ending: Use the Paranoia soul to fight Aguni, pick up the magic seal, and go back to the center of the castle. When you enter the boss door have Mina's tailsman equipped. You will now get a more extended version of the game and all you have to do is beat it.