I played it for a while before realizing that there might be a bug on the objects count! I came at a point where there weren't enough pipes in the first level
oh, I think I know what that might be, I thought I had solved it. Sometimes, if you time it just right, you might be able to superimpose two pipes together, if they are the same kind, it ends up looking like one disappeared, it's a very annoying bug regarding Area2D enter and exit signals that I was hoping was solved. I'll look into it. Thank you for spotting it!