Drakengard Cheats

How to fly a jet:
After finishing the Shinjuku free mission. Now pick sky mission mode and highlight the Chaos Dragon at the dragon selection prompt. Press Down and pick the "???" option to fly a jet.

Easy kills:
In the first or second mission, find a group of weak soldiers (the small ones in gray) and use your magic attack once (Triangle is default). Then, hit them with your sword or ax. To see if it worked, press L3 to see their health.
User Cheat by samIam

Attack enemies until you get the last flashing (on the weapon) combo attack. Press Triangle to get a bigger attack on the enemies.

Controlling weapons or magic:
When you hit enemies, use the Left Analog-stick to make a quick turn on every hit to enemies that want to attack you from the back.

Stronger weapon:
Do the expedition event and kill all the enemies with your weapon.

Alternate Endings:
Finish the flight missions with a time under 4:30 if you want the other endings.
User Cheat by skulswamp

Weapons from treasure boxes:
In every ground level when you kill everyone, except the targets, the game will state that a treasure box has appeared. Press R3 and your map will show you where, in a blue shaped box. Each treasure box on ground levels like this gives you a weapon.

Elf Village: Victors Spoils (spear)
First castle level environs: Hunters Blade
Ice third level: Poison Glaive

Dragon upgrades:
At 55,000 experience points, the dragon will upgrade to level 2.

To get a level 3 dragon, you must get more than 160,000 experience points.