The game mechanism is broken

I am at around 150 days in game. Suddenly, the satanists party start to attack me with advanced troops above lv10. I have killed 4 batches of troops but they are just keeping coming endlessly. Once they kill one or two of my veteran troops, the new one I got is only lv1 but I will have to face lv10 troops... This game is so broken and please fix it. The game has such good potential but it is so badly designed currently...

Firelping about Metro 2033: Wars, v1.6