Disk 5 (NG Disk) contains a small unfinished game called "Soldier of Fisla".
According to the Compile's newsletter Compile Club #21 page 8 this game was initially developed as ランダーの冒険III・フィスラの戦士 (Adventure of Randar III: Soldier of Fisla) but then everything was reformed including the subtitle, story and game system. The aborted prototype later became Disk 5/NG Disk.