I think you may have done something wrong. The {{World}} template seems to mess up sections (example). Also it's making the paragraph after the text bold (example). I'll try to fix it all up tomorrow, unless anyone wanted to try and figure it out in the meantime.
I've managed to fix a problem you didn't list, but it was in the second example.
Apparently, going back to no Enters didn't solve anything, which is not good at all, so I've analyzed the old Code, which is the same, except for the lack of Enters, and the lack of the NSMB2 Icons.
I worked out what was wrong; when Yami did this, the vertical slashes were put after the line of code, instead of before. The coding didn't have the vertical slashes in the correct place, so it was just reading it as the vertical slash after the line of code, which is why it messed up. Template:World-link is fixed now.