Originally Posted by Dillagence
I'm having the same issue trying to unlock 'Thrill of the chase', I've rinsed level 2-2 several times and have just about given up.
If it helps I also did the same level with no avail. It was not until I gave up, and was just playing level 3-2 (I think I was getting the scruffy graffiti) that it unlocked randomly. Maybe just the runners in 2-2 dont count.
Also it may have something to do with the direction the runners are running when you defeat them (away/towards the direction you need to go). I mostly took them down when they were travelling towards the direction I needed to go...I would jump over them then turn around and take them out as they were coming back. Also, another thing, when I unlocked the achievement I did a jump and roll into the runner, instead of a slide which I had done almost every other time. Maybe it is related to any of these coincidences. Just keep trying. Worst case save it for last, uninstall/reinstall, and hope for the best.