Below is a guide to completing two achievements on Assassin's Creed: Brotherhood.

---

Perfectionist - Achievement
To get this without a whole lot of trouble, just do the three kill streak challenges within the Virtual Training Room. The first two are easy enough, but the third one may require a few tries. Try and get a 14 or 15 kill streak and then just go nuts and rack up the kill tally as the score is best streak times the number of kills.

---

Serial Killer - Achievement
The best way to do this is to counter when a guard or Follower of Rumulous attacks you, then hold forward and "X" at another enemy, to do the Speed Killstreak. While in the animation of doing the Speed Killstreak, hold the action button (right trigger) and counter, when an enemy goes to attack you.