Originally Posted by Untitled Agent
Pressing activates the secondary mode of your currently held weapon. Kills with any weapon work, but the secondary for the laptop gun (Laptop sentry) involves the least amount of effort. Use laptop sentries where possible (which will also net you Deadly Laptop more quickly). This is cumulative across all game modes.
I played a Combat Simulator game and got over 130 kills using the sentry laptop gun, no achievement... Is it only unlockable with secondary kills in the campaign?