This "male birth control" thing is in my opinion just a stupid coup out to avoid adding pregnancy to the game. I don't get it, why make a game containing an island full of sluts, that want to get creampied and then telling the players "sorry, there is no pregnancy, maybe just as a bad ending". I do understand, that not everyone likes impregnation and pregnancy as a fetish, but at least consider to give the player the option for pregnancies for at least some girls. Some of the girls give already the impression that they want to get pregnant, why not moving on on that path?
Then there is the thing with the sandbox. It's confusing and not really intuitive. You're forced to constantly check EVERY FUCKING location to progress, some progress is block by flags that you need to get first and you have no clue what you have to do. There is a hint system, but if it just tells you "spend time with girl x", you're not really much wiser than before. And naturally for a sandbox game, you need to grind stats for every character available, counted 4. This stretches the gameplay time by a hugh chunk. There is already a good amount of content available, though. That's at least positive.
TL;DR nice looking renders, stupid coup out for avoiding pregnancy, horrible grind and even more horrible hint system. This needs a lot of work to be worth spending time.