Some of our games have code in them that locks them to a specific domain. Depending on how this was implemented, it could mean that HTTP://gameurl works, and HTTPS://gameurl does not work. To ensure that these games remained playable, we disabled HTTPS on those specific games. That includes today's Game of the Day, Decision: Medieval.
Does it follow from this that it's unsafe to log in to the site on these pages? I'm guessing so, but this is a question I get not infrequently and don't really know the answer. I usually tell users to play it safe and to log in on the main page or another secure page. But I don't actually know if it matters.