Castlevania: Circle of the Moon

1) Equip items with a combined strength penalty that is equal to or greater than your strength. While the game will indicate that you have 1 strength, actually having 1 strength is not enough to activate this glitch.
2) Activate the DSS card combo of your choice. Doesn't matter what it is - any DSS card combo will activate the glitch.

Once both conditions are met, attack power will instantly be raised to 99990 while both conditions hold true. While the game says that attack power is 9999, spinning the whip, which normally does 1/10th as much damage as striking with it, will also do 9999 damage when it hits, as if attack power was 99990 or higher. Unfortunately, actually using this glitch is basically impossible, due to the first requirement. The maximum attack power that you can have and still perform this trick is 210 (2 bear rings + dark armor), and, by the time you get these items, attack power will probably be far higher. Still, if you can pull it off, it's quite useful

You must have the Black Dog and Jupiter cards. When you are poisoned or cursed activate the Black Dog and Jupiter DSS combo. As soon as you activate it, deactivate it. You will now be poison or curse free.

To defeat Death very easily, just activate the Jupiter + Manticore DSS combo. His sickles cannot hit you, and by this point in the game you will probably never run out of MP because this combo will use it slower than you restore it.

To defeat the Dragon Zombies easily, whenever you get hurt, jump up to the platform by the door where you entered the room and activate the Jupiter + Mandragora DSS combo to heal yourself. A fireball may hit you every once in a while, but it is very rare.

When at the end of the Batlle Arena, where you get the Shinning Armor, Keep distance from the left wall and slide through the gap from a distance that you gon't fall out of it. You'll be at the entrance of the BA. Turn right and slide back in. The doors will be open. Keep killing until your health is low. You should gain a lot of exp. from the BA devil!

To play the game in the various modes with different attributes follow the method listed below

Equip two items that increase your attack power, such as the Strength Armband and the Solders Fatigue (you should have +250 attack power), then use either the Fire or Ice Shield. Next, equip two items that increase your defense, such as the Defense Armband and the Strongest Armor. You will do extra damage with your shield and take minimal damage from enemies. Note: Your whip will be weak, so use your shield when attacking.

This glitch makes Nathan go into Negative magic.

To do this:
1. Perform the trick to activate a DSS combo that is missing one or two cards (Activate a combo you already have, then while Nathan flashes during activation, goto the DSS screen and pick any combination you desire).
2. Make sure the incomplete combo you use works on use, NOT time (Like a summon, or whip).
3. Use the combo until you run out of magic.

If you did it right, and you had few enough ''excess'' magic left after you used the combo and ran out of magic, you should go into negative MP. You know for sure you did this right when you can goto the status screen and see that your MP is replaced with non-numerical characters (Like parenthesis, and |'s). Also, what this does is make you have to wait like normal until you go into positive MP, before you can activate any DSS combo again.

Normally when you finish the Battle Arena, you can play through again by going to the front door. However, there is a way to play the arena in reverse!
After you've beaten Battle Arena Devil, just stand halfway towards the exit in the "Shinning" Armor room. Slide out just enough to where you switch screens, but not far enough to exit the crawlspace. Slide back into the Arena and you'll find all the doors will be open again! Not only can you defeat the Devil again, but you can also run the entire Arena in reverse!

Note: Doing this glitch causes the Battle Arena doors to remain open, letting you skip rooms if you so desire. If you move forward however, the doors will close behind you again.

This powerup works best on a summon, but you can also do it on whips, swords, etc... Summon for example thunderbird. When you fly in the air, pause and switch to Mars+Black Dog (gives the best strength). The summon will be way more powerful! Good for killing hard enemies (Mimic Candle, Lilith, etc...)