Yikes indeed, I did sweat some very cold sweat when all of that happened. Never have I been so happy about the Greek House Free Pizza before!

Thanks for the tip, that's good to know! I probably would have gone for .odp and then wondered why it looks odd. I'm currently trying to figure out the so called slide masters in Open Office, since those would to my understanding be a way to not modify the fonts and text box sizes of every single slide separately. I haven't quite figured out how they work yet, though, but working on it.