I like it, Anax, I like it a lot! This is shaping up to be one of your best works, IMO.
Can I offer some (hopefully not to hard to implement) gameplay suggestions though?
For the trainer aspect, it seems a little boring to just figure out what each girl is weakest to and hit her with that, over and over - so maybe add a mechanic where the effect gets gradually weaker if you use the same room on the same girl consecutive times. That'll give in incentive to mix things up a little. If you really wanted to make things more complicated you could add some patterns to the effects - maybe Torture Room is so physically grueling it makes them more susceptible to the Relaxation Room if the Relaxation Room is used next; maybe the lingering high from the Shroom Room gives a girl a bit of a case of the munchies and makes them more susceptible to the Feeding Room. A system where each room has another it room it "prefers" to come right after wouldn't be too complex, I don't think, but would give us more of a reason to pay attention to who goes where, when.
For breeding, seems like certain bugs take longer? Also (maybe just my imagination) but seems like the higher corruption levels of the girls speed up the pregnancy time? Not 100% sure about either of those things though because the player doesn't get that info. Maybe add some info about approximate gestation times on the Barracks screens?
For the fights, I suggest that maybe corrupting one or more of the girls unlocks the ability to see how many enemies you're up against that day, and then maybe later on unlocking the ability to see what kinds of enemies they will be, and then finally unlocking an ability to see exactly what order the humans are going to attack in. Just would add another layer of tactical decision-making, right now you don't have much information about what you're going to fight so it's pretty much just "throw in my bug that's best against this human (or at least not weak against this human), keep going till it dies, then rinse and repeat." If we know what else is coming later in the fight we might make different choices, which keeps things interesting!