it looks like there are a couple of bugs in the code. Because the project updates the files with CodeGym's own code, I don't believe these bugs are my fault (not that I don't make lots of mistakes, just that I think these ones aren't caused by me). The addFile() function doesn't rewrite the original contents of the zip file back to the archive. Everything is overwritten by the new file added. The extractAll() function does not work for nexted files. Can anyone who has completed this confirm this? Or anyone who works for CodeGym? Or did I screw something up along the way? (always a good chance of the latter)