How do you get the last two videos in Starfy

If I'm talking about the right game, this should be the answer.

Story 23: Beat "Big Bossdown" (located in the case after beating the game) using Starly (or Stapy in Japanese). There is no specific time you must acheive.

Story 24: Beat Mashtooth twice (in other words, beat the "Mashtooth's Last Stand" level twice) to unlock the Missing Chapter. How Bunston ended up in Pufftop.