The AR2 (aka Overwatch Standard Issue Pulse Rifle) is a weapon commonly used by the combine elites. It uses a similar ammo clip as the SMG. Its ALT fire is a very useful addition, allowing users to shoot a combine ball, a large electric particle beam that kills targets instantly.
The AR2 is first given to you when you kill the first group of Overwatch Soldier on your way to Nova Prospekt. Its good.
The Good Deeds hacks Edit
Well you can do cool things with it. Hoovy likes bagels as well. A secret tactic to killing the Jeremy Sutton boss on the chapter Vortigaunts Unite, is simply to fire 3 combine balls up his nostrils, causing a catostrophic explosion and his demise.