I got some lag during the Duels with the NPC hotties on my old Core2Duo 2.14 MacBook 5,2 (Mid 2009), so the targeting interface was actually lagging a lot. But with a little bit of patience and a few more potions, I got through.
Just wanted to bring it up so maybe you guys or some other excited players could maybe check on it to see if it's just my hardware lagging or a code thing.
The Dark Knight is intentionally over-powered, I presume? ;-)