Play the "Casino" level and start killing people. Allow yourself to be spotted up to two times, then kill a cop to get the attention of the FBI. When there are between eight to ten people remaining, kill someone and allow yourself to be seen. Once the police arrive, run up to the stage, stand next to the swinging cable, and repeatedly press [Trap]. If timed correctly, the cop will die and the FBI will appear. Kill the remaining guests without running into them. Note: You can use any type of trap to kill the officer, as well as the gumball machine next to the kitchen.
Easy "Engineer" achievement
Successfully complete three levels without using traps. It is recommended to play as the cop, as he cannot use traps, preventing accidental use of them. Playing the same level three times consecutively will qualify.
Easy "Hellhound", "Murderer", or "Slayer" achievements
Throw a smoke (recommended) or stun grenade into a group and wait nearby. After it explodes, run in and kill as many people as possible. The red symbol that appears above their heads indicates they cannot see anything and also cannot be seen by others, making it easier for you to escape undetected.
Easy "Jockey" and "Unbowed" achievements
Play the final level, "Underground Sick". Activate the horse or zebra. Activate the steam at the very bottom and walk into it. Repeat this process as many times as needed.
Easy "Loser" achievement
Play the "Beach Party" as the woman. Go to the phone, make a call, and allow the zombies to appear. After they infect everyone, kill them until only one remains. Then, go to the streets and get run over by a car.
Easy "Ninja" achievement
Play the "Beach Party" as the woman. Go to the phone, make a call, and allow the zombies to appear. After they infect everyone, begin killing them. The other zombies will ignore the dead ones. You will get the "Ninja" achievement after killing the final one.
Easy "Unbowed" achievement
Play the final level, "Underground Sick", and walk down to the horse. Allow it to kill you with a kick, then reload the level and repeat the process as many times as needed.
Various Achievements
Complete the following achievements to unlock Microsoft Gamerscore points.