Singleplayer is too boring but multyplayer is too stressful? No problem. The levels are designed for single player mode but you can compete for best results with other players if you feels like it.
Anyone can go mad from billion numbers such as hit, crit, armor, cooldown, range etc. We made only 1 parameter that includes health and attack stats - Condition. If the personage is tired or wounded he will shoot worse, his health will decrease and he can't do some kind of actions.
We understand that you probably don't have much time to play. So 5-10 min is enough for one mission and you'll have time for family or friends! And if you don't like your progress you always can replay missions.