First of all, congratulations! Both on the game, and on the engagement!
Second of all, this is some exceptionally groovy music.
You've taken a pretty straight-forward concept and executed nicely on it! The jumps felt a little floaty/hard-to-control to me, but that's personal preference, still plenty enjoyable to run through.
One potential bug to report: after I went through one of the portals, I found the screen would occasionally go blank for a bit after collecting a diamond. Any idea what might've been causing that?