Hi Zakaria,
Thank you for the video and I'm glad you had fun playing my game. The game started out as one level, using Godot tutorials on how to make a maze level, and I went and expanded on it.
I apologize for the line that was showing up in several of the levels. It was there because there's more than one piece to the level floor. I went and extended the width of the first map floor section for the levels that needed it, though, and now that's fixed. Also, the enemy in level 2 that wasn't moving, wasn't supposed to be like that. I didn't even realize that, though, until your video, so thank you for that. I went and fixed it, though. Sorry about that.