This is an incredible first build and I am very interested in any further content. 3D animated FMG games are quite rare, so this is a real treat. The only active creator I can think of is Myon-San and this game reminds me a lot of all the things I like about their games.
The models are well done and our protagonist in particular looks well proportioned. Not every character is exactly up my alley, but hey, that's what the sandbox system is for. The story hook is straightforward, but it just works. It also helps that Jane, though quite horny, is a nice person. The gameplay elements are pretty simple, but they do what they need to.
I'd love to see a couple more story events to show how much bigger Jane has gotten and to simply get to know the characters more. If I may offer one point of critique though, I personally don't really like the visions of future growth stages, as they kinda feel like a spoiler. At least to me, being suprised by the transformations is half the fun, so seeing the final stages in the menu is kinda anticlimactic. All in all though, this is an amazing first release and I couldn't be more excited for future updates.