Great concept and fun retro implementation. A bit of feedback:
You can give a male breasts - the futanari option. However, I couldn't find a way to grow those breasts. It would be fantastic if futanaris could not only drinks pussy juice and milk (to grow their balls and cocks, as every male can) but also can drink cum from another male to grow their breasts.
The various rooms you can purchase do little more than change the background. It would be cool if each room was different. Ideas:
Factory - Have newly recruited girls start out as fully dressed factory workers. If they wander to close to a man, he randomly grabs them and fucks their faces or pussies. As this makes them grow, their clothes start to fall off.
Bathroom - Here girls can use stalls to "pee", get rid of excess milk and pussy juice without growing a man. Sometimes a thug enters and fucks a girl. The more girls you have here, the more frequent the thugs appear, so with four girls you could end up with an orgy.
Sauna - A girl enters wrapped in a towel. For girls with large tits and bellies, the towels hide next to nothing. Random men enter and exit the sauna, and jack off. If a girl is close to a climaxing man, he forces his cock into her mouth or pussy to fill her up.
Hotel - Add four beds to this room. Random men (with random cock and ball sizes) appear if a girl lies down in a bed and fucks her face or pussy. There's a random chance he stays hard after cumming, to fuck her a second time. Sometimes when this happens a second man gets impatient and appears so they can fuck both her face and pussy at the same time.
The cum spa has its floor covered in cum. But only the men can lie in it, which has no effect. Not sure how to make it actually impactful... How about the cum level steadily rising, threatening to drown the men. The girls need to continuously drink cum from the floor to keep the room operational, at the cost of having their breasts grow of course.
Cock Land - you already have huge cocks cumming. But I couldn't get a girl to drink from these. A woman shouldn't need a male here, she could just fuck the statues and drink their cum. There could even be monsters that roam around to fuck girls.
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There's no real challenge. This is a "game" much in the style of Super Deep Throat, and nothing wrong with that.
Could be interesting if you could fail somehow (perhaps as its own game mode): If you place a new girl on too large a cock, or on a cock with too large balls, she pops like a balloon and you have to purchase a new girl. There would be time to take her off the cock in time to save her, even if the rest of the ejaculation might be wasted. If the girl's belly is large enough, that means she can accommodate huge cocks and huge amounts of cum. Unless, of course, you give her huge amounts of cum repeatedly, then she might pop anyway.
There's also no real end game. Again this is fine, but one thing I didn't love was how you have to manually adminster girls and guys between rooms. Yes, you get a flashing red screen to notify you somebody is about to cum somewhere, but I'd much prefer a less hectic approach.
Would be nice if you could "educate" the girls, nominate factory foremen (fore girls?), or some such, where these girls climb onto cocks themselves when they are about to erupt. These girls also find girls with no task (girls aimlessly walking around) and assign them a guy to start to jack off.
I think setting up an end game where girls grow and guys cum by themselves is more interesting than "whack a mole" where you make a "game" out of frantically switching between rooms to see which cocks are about to go off. Just my 2 cents.
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An alternative idea to an end game would be to tie into the story (you running a fertilization factory or whatever).
By that I mean you could have various rich men make offers for your prize women - girls with well developed bellies and breasts, girls that gush vaginal fluids and drool breast milk like crazy. If you get rewarded in money that could be like a score, meaning you would have a reason to keep playing even after you've seen everything the game has to offer, just to "beat the high score", the amount of dollars you've successfully sold girls for.
(I know you currently get paid lots of cum if you sell a grown girl, but how about replacing the currency for something you can use as a high score)
Could be cool if this isn't a mindless transaction and the girl gets to say her opinion before you accept any deal. If you're being purchased by an athletic sports star that's more attractive than if a skeevy fat mafia fuck or some oil sheik bids on you, for example.
Not only would this add "endless" replayability, it would also give a legit reason to train up new girls to replace the sold ones.
And if you implement the suggestion where girls can pop if they take too much cum, you have a legit skill game - to get the girl off the huge cock before she pops, but to stay there long enough to take enough cum to swell nicely.