[After playing v1.40.18]
For the most part I found the gameplay quite entertaining, more than the story itself or the porn. Though is quite grindy, if you like the style it won't feel boring.
I have to say that it's one of the games in Ren'Py that surprised me the most as it does some things I wasn't even sure that could be done in Ren'Py (that also makes that sometimes things don't work as good as other games, like battles, but still, it's perfectly fine). I would have prefered some managing elements were better developed and more connected (not having missions in one PC in a room and the stock you manage in a different room and then only having the possibility to know how much material you have in the hangar in yet another different location, needing to go to one place to other to remember how much you have, but anyway, it's still managable.
Story is fine, but still lacks something and some characters are not exactly used enough. Also, though the game is reasonably "Completed", let's be honest: there were many obvious routes that were going to be created and were just cut to put a quick complete, and character stories that never get explored. And It would be a nice detail if the game still receives a new update to take out all the "in future version" and the items that never get used (like the tickets for advanced training) and the options that weren't developed (pet tricks, for example). When you're playing a game apparently "complete" it creates unnecessary expectations.
Porn-wise is ok, graphics are nice and the sex, training and that are done ok, but to be fair it's usually just a pic or a couple pics here and there.
It certainly was enjoyable and yv0751 seems to be a interesting developer to follow, there's a lot of potential there.