Story related and unmissable.
you'll be attacked outside by 2 bosses: Garurumon and Monzaemon.
The map layout is pretty bland and aside from the 2 bosses you have some Togemon and Gotsumon to deal with as well.
Your best offense is the Data type Digimon to deal with the bosses and Virus types for the minions.
You must defeat everyone to win the battle.