This is more of a glitch, but in the battle against Millenuimon, if you pause the game his head dissapears
Terriermon is a good DigiMon to use.Its Up and B attack lets you do about the same amount of damage when its in DigiVolution Form
This is easy as well, Just beat the game on easy, normal or hard with any digimon and get a score of 300 or over at the end. lopmon, gabumon, or blackagumon are the best ones to use but veemon is good as well.
This is easy, just beat the game with every digimon.