Aside from the embed pck option everything seems to be like default. That's really weird. Are you using 3.3.3? Maybe you could try exporting it with an older version (it has happened to me that sometimes new versions break stuff in my games, even if they're small updates like 3.3.3)
alright, I decided to try a few things.
first of all, I had an older build on me, so I exported it from that.
also, I figured the filesize may have been part of the issue, so I had it export from both versions without all the music which doesn't show up in the demo. try em both out and report back to me