If earlier during the attack of numerical blocks you had to rely only on your own dexterity and accuracy in shooting, but in the game FireLine: Merge Defense you will need completely different qualities. First of all, you must become a strategist and tactician, because the success of your defense depends on this. The gun will shoot by itself and without your efforts, but you have to endlessly improve the gun so that it fires faster, more shells, in addition, you will increase the number of guns, but not to infinity. To raise the level of guns, on a special field, make connections of pairs of guns with the same parameters in FireLine: Merge Defense.