From the campaign:
The game features fast-paced combat and a unique stealth system that gives agents the option of using silence or violence to take on the base.
Time itself is a resource, agents can ‘spend time’ to accomplish a variety of actions (from breaching doors to sabotaging the base’s generator) but they must spend it with care – every minute takes the world closer to doomsday and victory for the SWORD.
It’s time to spy… or die trying!