This reminds me a lot of Pink Slurp Engineer, with the whole three pipes, three lights thing, but the gameplay on this is different, and it's inflation instead of hypnosis and HG expansion. Could this be inspired by it in some way?
On a side note, I will be eagerly awaiting more updates to this. At the moment, it feels pretty grindy, what with the fact that it takes so many plays to get any amount of upgrades, and you essentially need to have upgrades to win. But, in the future when there are more girls to pick from, I'm sure it'll be less so, since you can just alternate between them and it'll feel more fresh.
Some things I could recommend in the next update, besides what you've already listed, is a mode or option for the inflation to just enlarge some of the body parts but not others, like you could pick just belly or just boobs. Or maybe that could be a thing for different characters, like some characters just do boobs instead of the full deal. And also maybe a gallery, which would allow you to see all the levels of inflation you've reached so far, since in this sort of game I often feel unable to appreciate the growth since I'm too focused on actually playing the minigame.