Level 0 isn't ever actually locked to begin with, I just didn't consider that you could exit the level without completing it but I think beating the level and pressing Escape take about the same level of effort.
I didn't notice the other things, thanks for letting me know :)
I knew about this too! I thought it was a neat thing to find so I left it in! I almost made an optional level that required you to do it but decided against it.
