Get Good Ending:
Get the Stone of Sealing before fighting Sol. Then beat the Body of God in the Royal Tower to get the good ending.

Unlock Helina In Versus Mode:
You need to defeat Helina in an arena. After you defeat the boss in the Scared Arena (Area 2), go west and find Helina's Arena. Note you need to have the following prerequisites or Helina will not fight:
Your character's Neutral Skill is 6 or more.
Defeat all bosses in the first arena.
Defeat the unknown man or Kendarie Knight blocking the exit.

Unlock Katia In Versus Mode:
After defeating the boss in Scared Arena 2, head north and fight Katia. Defeat her and an option saying, "Do you want to take on Katia's responsibilities?" Selecting yes will download your card collection from the first game (from your Lost Kingdom save file) and add it to your LK2 save.

WARNING: You can only download your LK1 card collection to your LK2 save once, and at this point in the game.

Saving afterwards will unlock Katia.

Unlock Kendarie Warrior In Versus Mode:
Defeat the Kendarie Boss in the Kendarie Fortress in Area 1.

Unlock Rashiannu In Versus Mode:
Clear the Royal Tower Upper Floor on single player mode. Don't forget to save the game!

Unlock Thalnos In Versus Mode:
After you beat Leod and Helena in Scared Arena 2 (after clearing the game once), fight Thalnos in the north most doorway of the arena. Deck him and save the game.

Unlock Urbur Cultist In Versus Mode:
Defeat an Urbur Cultist, clear the stage and save. This selection is listed as "Unknown" on the Versus mode screen for some reason.

Glitch: Expensive Card Duplication Trick:
You will need two controllers for this to work. To copy cards without stopping at a card shop, you must first make three files:
The file with the cards you want copied.
A exact copy of the first file.
A fresh file. Right at the beginning.
Afterwards, go to Versus Mode and load the replica of the first file with controller one and go to BET. Once there bet the card(s) you want copied.

Then with controller two load the fresh, new file and go to BET. Now bet any card. Intentionally allow controller two to win. Now load file #1 with controller one and bet a card you don't want.

Now load file #3 and bet the cards won from in the previous battle. Intentionally let player one win and immediately after the battle and you will have a duplicated of that card with same EXP. Try this with a capture card and you'll be very happy.