That is quite creative, but I have a few remarks.
- You should remove typos.
- The lines should move with the heart for giving the sense of speed when falling.
- The Space bar is never a good choice for a one-button game. Maybe choose the "any key" approach, or choose a key that responds more quickly.
- It's actually pretty bad that the song has to start again during the game and be suddenly cut at the end. I suggest that you make it loop even when the player falls to his death, and that you make it go on even when the final screen is reached.
Last but not least, does it have anything to do here ? I mean, I have played through, so that I could give an opinion and help you make it even better before her birthday, but nobody here actually gives a damn about your life, your addiction to a video game, her fear of heights, and your trip to Paris. Sorry to make it harsh, but couldn't you just let two or three friends of yours play the game and make some suggestions ?
From a personal point of view, I would say : stop playing Halo that much, and with something like this, she may be expecting something else than just "happy birthday" (I was expecting a "will you officially become my fiancee ?" or even a "will you marry me ?" at the end of this "game", as you try and make a summary of what you've been through, and mention that you cannot even imagine yourself with someone else).
Still, this has nothing to do on NG in my opinion. If I were you, I would not have put such personal stuff here in the first place. 3 and a half stars in this review, for the idea and the way you made it, but the official rating will be 0, because this is not the stuff that should make it to a website like NG.