Three days of hunting Howlers passed before Zane and the others were able to get enough kills to fulfill the requirements for their achievements. It appeared that, unlike most MMORPGs that Zane had played in his youth, the party system in this new world did not apply to one's achievements.
Meaning that every time Zane dealt the death blow to a Howler, he would get the recorded progress for it, and only him. Even if Elena froze the Howler in time, or Olivia paralyzed the creature with their skills, the kill was officially given to whoever dealt the final blow.
Zane, of course, suspected this was by design, to create discord between the living. As human beings, competition for resources was an innate and visceral experience. In this brave new world, leveling up was a competition, not only for resources, but for power.