For some reason there is a max level with each installment and most of the contracts give very low money for a lot of game requirements. which means an annoying cycle of (wake up, do 3-4 contracts, go to sleep) and repeat for several days until you get enough money.
So Yeah, the structure is very weird for episodes based game. I played the main story only and some side missions (the ones required for the main story). The grinding is tedious, the game is so inconsistent with it's visual representation and art direction, some of the scenes are good, others not so much. i'll wait for the game to come in visual novel form and give it another try, hopefully they will iron out most of the problems.