The tag wiki for old-games clearly states it should be for compatibility issues with no-longer-supported games, and I think that's a useful tag to have; unfortunately the tag name itself is not very informative, and a lot of identify-this-game questions and even other questions about relatively old games get tagged with it.
I think the tag should either be altogether removed or at least be renamed to more explicitly represent its purpose, for example old-games-compatibility or something like that.
EDIT: bump. The tag is still being abused. With 6 upvotes on Matthew's answer and no counter opinions, can we kill it now?