Valdiuss

I haven't played this game for a month or so, and today started it up again. There was a new patch so I went ahead and downloaded it, then proceeded to play the game (started a new game on easy mode). I know I got thousands of kills (in fact, when I sensed there was a problem with this achievement, I got more than 1000 kills on a single level) and still no killing spree achievement! Is anyone else having this problem?