Breach is an action-shooter based heavily on real CIA tactics. Aside from this authenticity, its primary feature is destruction. Breach creates destruction on the fly. A solid wall can become a pile of bricks. This changes typical game strategies because the world is not a static shell. You can create your own vantage points, change routes, or completely level an enemy's base.
By default, it's 1st-person. It switches to 3rd-person when using cover, however. Breach only features online multiplayer (16 players per session). There is no single-player campaign.