Glitches

Network dupe
To dupe items, you need to be connected in a multiplayer game. The character with the item gives it to another player, and doesn't save the game when exiting. The player who receives the items needs to save the game. When both players reload the game, they will both have the item.

127+ Available Attribute Points Glitch
If you save and exit a game while having more than 127 available attribute points, you will lose all the points permanently from that save. You will notice that every time you load that save, the level-up option is gone hence all the available attribute points you saved are gone as well. To prevent this glitch, you have to keep the numbers down below 127 before save and exit the game.

Secrets

See when enemies are invisible or off screen.
If there is an enemy that is invisible or closely off screen near you, let your character stand still and his position should change from standing to an attacking stance. This means there are enemies ahead.

Temporarily stop kamikaze attacks.
If a kamikaze monster (one who explodes on impact) is charging for you, start switching between Weapon and Bow by pressing R and X. Doing this very fast will stop the kamikaze monster for just a second while he is right at you, giving you a chance to block the attack.

Reach to a High Level
After you made a character, level him/her for a while and then restart the story. You will still have all your equipment and be at the same level. Now you can get to level 20 before you leave Aven!

Find Bosses in Dungeons Faster
If you hold R and hit Square, the map zooms in, and if you do it again, it disappears. When you hit once more the map will reappear, but the game refits it to normal size. In the split second it does this, you sometimes can see the Boss's icon on the map that you wouldn't normally be able to see with the zoom function. This gives you a pretty good idea where the boss is and allows you to navigate appropiately. You can do this as many times as you want to keep checking.