Okies, here's how things are.
Dungeon Keeper was made by Bullfrog in 1997, which means it is subject to 10-year protection period.
Wikipedia specifies that to be the month of July, which is confirmed by multiple other sources.
Therefore, Dungeon Keeper will become Abandonware (and thus eligible for addition to Abandonia) in August, just three months from now.
Reminder to self: make a Horned Reaper emoticon for the forum.
Make that several.