About the minigames:

- The Gravity one is too hard
- Line Breaker is hard also but with some luck you can get 2-3 stars

The other ones are easy once you understand timing and mechanics.

For me the problem is energy of the girls, I have 2 at girlfriend level and without giving them energy drinks is almost impossible to raise all bars before she needs to go bed again. And there is no Energy drink option for coins, only diamonds, so unless you pay money for it,... I don't know it would be next level or when premium status finishes and girls start losing affection when bars are empty.