I really like the concept and I'm SUCH a chemistry nerd (though I am only doing exams myself, heh) . The GUI is cute, the colours are eye-catching and the chemistry puns were so, so bad (I'm a sucker for bad puns, even more so nerdy ones) - I love it. There are a couple things I'd like to mention though:
The in-game menu buttons don't exactly align with where they are, so I had to keep clicking lower, where the actual button was to return to the game after saving.
This is my inner nerd speaking, and a minor detail, but "Which liquid has the highest boiling point?" and giving the answers as HF, HCl, HBr, and HI might not be the best answers, since they're all gases at room temperature at the very least... unless you're talking about when they're dissolved in water. (save for HF, which is only liquid at just below average room temperature.) [Also, the hydrogen halides in general is pretty dodgy to talk about trends in boiling/melting points.]
I think for Marina's eyes, I think they look "creepy" for lack of a better term because we can see the bottom of her irises on her normal face? I'm not exactly sure though.
That's all I have for now. I'll keep an eye on this! :D