did you make sure to optimize your assets. it sounds to me like you used uncompressed images and sounds for everything.
Viewing post in "Split" the ZIP files for WIN/MAC games?
I wouldn't know tbh, I'm not all that savvy! T_T haha. I used WEBM and OGV for videos, OGG for BGMs and SFX.... It is just a demo for a really big project though so it's not like I could just stop working on it and leave it in a weird state where a random route was only half finished or something T_T