It's good so far! I do have a few suggestions, though:
1. A proper pause menu, or if there is one a way to check the controls. Potentially also a way to restart the day? I had to straight up restart the game once since I got shoved into a wall.
2. Repeat customers! Characters, not necessarily with unique models, that keep returning. Maybe they pay more? Just a way to show off the differences between them and newer customers with fewer gains.
3. In league with the previous suggestion, maybe a way to tell girls apart further. Be it simply through a name or some other way, it'd be neat. Maybe a simple stat display above their heads with their name and growth stages on it? Just spitballing; I don't know what's allowed and affordable.
4. Obviously, and I know this is planned, other machines that enhance other things. Redundant, I'm aware, but it still needs mentioning. Maybe higher "tiers", so to speak, of the current machines already in? With either more radical or faster effects.
It's still a solid game in its current (very) unfinished state, keep up the good work.