VANQUISH

First, you must get into cover. To get into cover, get close to a fixed object such as a wall or something and press . While you're in cover, press to light up a cigarette. Sam will light up a smoke, then throw it away which will distract the robots and they will start shooting at the cigarette. Shoot the robots while they're distracted. If you happen to destroy 2 or more robots distracted from a single cigarette, you will get the "Auld Lang Syne" achievement. If you manage to kill 10 robots during a single mission, you'll be rewarded with the "Smoke 'em if ya got 'em!" achievement. Note that you only have 3 cigarettes per mission. To see how many cigarettes you have left, look at the bottom right of your screen. It's that little 'stick' above your weapons that looks like this ""

As shown in the video below, a great spot to get this achievement, is near the end of Act 3-5 (Despair) right before you have to board the Kreon. On this particular area, the Kreon will be on your left side. You will find plenty of green "Marines" ammo crates in this area. Similar to the rocket launcher and lock-on laser achievement descriptions, if you don't have a rocket launcher on this section, kick the ammo crates open, and keep reloading last checkpoint and repeating previous steps until you get a rocket launcher. Then, let yourself get killed, so that you'll have the rocket launcher right from the start. Once you do have it, and as you move toward the Kreon, you'll be welcomed by a bunch of enemy robots and Romanovs on your left side when the hatch opens up. Get into cover, light up a cigarette, throw it away, and as soon as they all start shooting your cigarette, fire a few missiles at them. If you didn't get it and ran out of smokes, reload the last checkpoint. It is really easy.