Gameplay: Quantity of alien missions depends on difficulty level.

Now works next algorithm of missions generator (the wave of missions):
1. Each month generated one terror mission and one random mission.
2. If monthsPassed > 5, then generated 2 terror mission and 2 random mission.
Quantity of missions does not depend on difficulty level.

I believe, this is wrong. Quantity of missions should depend on the difficulty level. In vanilla Xcom, difficulty level affected on number of missions.

I suggest next algorithm of generator:
Each month, will generate one terror mission and several random missions.
Beginner: 1 terror + 1 random.
Experienced: 1 terror + 2 random.
Veteran: 1 terror + 3 random.
Genius: 1 terror + 4 random.
Superhuman: 1 terror + 5 random.

After 5 passed months, quantity of missions will be doubled.
Of course, real quantity will be less, because duplicated waves in each region will be removed.