I had an idea, since the database tracks who kills you the most and who you kill the most, is it possible to add achievements if you kill someone who has killed you more than you've killed them, and they're in the top 10 list? It could be even too. Say I have 10 kills on Klypto and he has 10 kills on me, and he's #2 on my most killed/killed by list. I could get a "One Upped Rival" achievement for killing him, or get a negative achievement for letting him kill me.
I'm unsure if it is too complex for the API, but thought it would add some cool flavor to the tracker.
BTW, I love the tracker. Keep up the great work!