Alternate Reality: The Dungeon

Head into any guild, and type in 666. You will gain a lot of HP, but as a side effect, you will also become very evil in-game.

Go to a Stairwell and type the number 853-1212, including the dash. This will put a new spell in your inventory, called the Tac Nuke (95%). The spell can cause upwards of 1000 damage to multiple foes at a time.

Head to the Golden Apple, then go to the screen that gives you the option to obtain it. Press Y, then as quickly as you can follow it up with D. If you were quick enough, you will go through your drop item menu with the Golden Apple in your inventory. Drop it. You will now have the HP bonus from the Apple, but not only that, you can pick it up and drop it for an infinite amount of times and an infinite amount of HP bonuses (again, providing you can press Y and D quickly enough).

Equip a one-of-a-kind item with a special effect. Enter the Dwarven Smithy on Level 2, and try to sell him the item. He will refuse to buy it, but the item will be removed from your equipment and into your inventory, while the effect will still be there. This can be stacked as many times as you wish.

Go to learn a spell at a Guild that can raise one of your stats (make sure you have the maximum number of spells you can memorize at that point in time). Go outside, and cast the spell to increase one of your stats. Then, with the spell still in effect, head back into the guild and learn a new spell, and unlearn the stat-gaining spell. The status boost will become permanent, and you can do this as many times as you wish with the same spell.