[Feedback of v0.07]
+Amazing modeling
+Great animations
+Decent puzzles
-Backtracking to Sebastian is a bit tedious
-No animated money-shots/cum
-Obviously early build, low content
This is shaping up very nicely. The art direction, modeling, and animations are all great. The movement and controls are all quite well handled as well. It reminds me of the Harry Potter games in some ways, which makes me nostalgic for the flying mini-games. Good job.
My biggest gripe is the lack of cumming for the various animated sex scenes. During the story, there are artistic stills of cumming, but you can't view those in the gallery. It's understandable -- animation for liquids, much less liquids with cum's viscosity, is difficult. Each cumming scene is a whole extra animation, and one that people will only see for somewhere between 5-10 seconds each animation cycle. Still, it's a very effective touch, and there are some workarounds. Sound effects only could work as a placeholder, or even be fine for the final product as long as all cum shots are internal/hidden from view. A small cum-drip model animated coming out of her orifice would also work. Heck, you could even flash in some artistic stills of the cum shots somewhere onscreen, and I honestly don't think people would mind that much.
Aside from that, all my other complaints are minor. I would suggest making sure players don't have to backtrack too often, something which I think you're already keenly aware of since there are teleport platforms in the game. Also, adding a "To Title" button in the pause menu would be fantastic. The story is fun, but it'd be nice to be able to reach the gallery without closing the whole program.
Altogether, this is a fine project that I look forward to seeing more progress on. I wish you the best of luck in designing more puzzles and scenarios. My advice would be to take inspiration from everything -- look at other puzzle games and take note of what they accomplish and how they do it.