Thanks for the tip, pcuser. I've been playing on here for a few months but only made an account a few days ago. Had to close the window on a couple games at different times when *ahem* I ought to have been doing other work on the computer
Didn't know that would count as failed, and didn't know there was anything I could do about it until I read your post.
Went back through the "recent games" list to finish the ones that were still within 24 hours, but missed 2 that were a bit older. So I guess I'll never have 100% but at least I know for next time