I tried to run it but it said this, can I substitute something in place of BGFILL?

プレイ済み
So then what are the numbers for Up, Down, Left, and Right?
0そうだね プレイ済み
It says there's a break on 0:4, I don't see anything wrong, help?

プレイ済み
Is there any way to make your own music?

プレイ済み
Is this application worth it? This seems really nice for making simple games, and I want to get into programming games.
0そうだね未プレイ