You're being chased by the enemy and have to escape. Fight their drones, turrets and vehicles on a train through several levels and several waves.
You can choose between the Story or the Wave Mode. In Story Mode, you have to go through multiple level after another and defeat the end bosses in each level.
In the Wave Mode, you encounter waves of enemies and during a pause, you can buy new weapons.
Use different types of weapons to deal as much as damage with the least amount of bullets. You can pick between a pistol, a shotgun, a machine gun and a grenade launcher. Dodge their attacks during the bullet time. The bullet time activates as soon as a enemy bullet gets close, dodge it by physically moving in the room while the time is slowed down.