For first (if you want to sell your game over CIS region (Russia/Ukraine etc)) make available payments over Webmoney and QIWI because 99% of russians will not going to fuck their brains over two weeks and more to make yourself a credit card with electronic payments enabled. This is not an advice or suggestions - this is what reality is.

For the second (it will be a very important advice) make a movement restraint system. Something like two-hands system. Any method to restraint movement for at least of one bodypart because when tou trying to move her hand whole body is moving and reaching of certain pose it's like a charade or turn-based strategy.

Further will be usual advices
Make a free mode after completing story that allows to do anything with girls during story completition and different character select.
Lifting girl to place her on the table for example is very-very difficult. Please do something with that)
Make an option with penis at angle greater than 90 degrees from vertical down (not horizontal as higher point).
Give them a panties (to girls i mean) .
That's all. I have a lot more advices but those are will be a willings not the important things.

PS For now your game is quite unique. Thanks for your job.

By the way, without movement restraint there's a lot of funny things happening) I wanted to fuck Samantha in gym when she was sleeping. After relocating her to usable position and putting dick in her ass she stucked on it and i was running over the gym, laughing like a mad, with girl stucked on my penis.

And "Yes", I saw topic with control rings, I just proposing a different method like holding something with one hand while moving something with other.
Orgasm or other animated reactions already was in request but want mention about it too)