This one, like that one, contains a battle system where you tap as the cursor moves up and down a bar in order to attack the enemy and stop their attacks. As well as increasing your stats in a strategic manner in preparation for the later battles in the round, especially the boss battle.
The green and yellow squares are the normal attacks, while the red ones, which move, represent a coming enemy attack. If the red one reaches your side, you’ll get attacked, so tap those ones to ward them off.
The purple squares cannot be defeated, so let them pass so they don’t block your attempts to tap the other blocks.