Disk 5 (NG Disk) contains a small unfinished game called "Soldier of Fisla".
According to #21/22 of Compile Club, Compile's newsletter, this game was initially developed under the title ランダーの冒険III・フィスラの戦士 (Adventure of Randar III: Soldier of Fisla) but Compile then decided to reform everything including the subtitle, story and game system. The aborted prototype later became Disk 5/NG Disk.