Half-Life for Dreamcast. I guess it wasn't really that bad, considering it was never finished, but it was the first one to come to mind. Every time you saved, the file size increased by a certain proportion, so that eventually you'd be completely unable to save your progress. You could work around this with level skipping passwords/codes, but due to general bugginess and difficulty I lost interest at that point. Still never played the first Half-Life to this day. That's what you get when you own macs your whole life.