Adding music should be easy enough. I believe the tutorials page on the wiki has a link for an "adding sound effects plus music" tutorial. Plus, the "Verve! A game of skill!" topic has instructions on how to do just that.
I played it, and I thought it wasn't too shabby. It's short and to the point, and while I could have stood to see some different levels, I liked how the challenges were always different. I wish you would have used the gravity changers more- those were pretty neat.
Some things DO need to be addressed should you ever release a version 2 or something:
-There is absolutely no point in having the "how to control the game" node so far away from the player, who (by the time he or she has reached the node) already figured out how to jump. Players need to know how to control from the get-go, and there was an awkward period when I started the game where I kept on pressing buttons to figure out how to jump.
-If there is going to be one maneuver, jump, then I think it should be the space bar. Just a preference of mine, since it kinda makes things simpler (and on some computers if you repeatedly press shift the computer makes a nasty noise and a pop-up shows up asking you some technical jargon)
-I think the bunny hop thing is kinda superfluous; it doesn't really need to be there. You can just uncheck that box on the Construct application page, under properties>>"Allow bunny hop"
-Most importantly, some of your levels rely on you finding secret passages. While this is a good idea in and of itself, I think there is a serious design flaw in play when the player is completely and utterly clueless on how to proceed, relying on trial and error.
Take for instance, the "that spike looks weird" level. I had no clue what that meant, so I repeatedly rammed into every available spike until I found the solution. I think there should be a graphical cue to nudge the player in the right direction: maybe a slightly different appearance or some off-coloring, or something. I mean, the text itself wasn't even close to the spike in question; I kept on experimenting on the wrong set of spikes till I finally gave up and tried EVERY one of them till I found the one.
So mainly, I think that graphical cues are important to find out secret passages and what-not, because without out it, it turns into "let's ram into every tile to see if it works this time" which is anything but fun.
Now, on the positive side, I like the graphics used, and I like the simplistic concept. As stated earlier, I liked the increasing complexity of the levels (though some of the levels where you just placed one orb close to a spike were a let-down, considering the cool levels that happened prior to that); some of the mechanics (like the blue orbs and the gravity machines) were pretty cool and unique.
A lot of the mistakes here are what I'd call beginner mistakes, but the good thing about beginner mistakes is that they often can be easily rectified as the maker grows in skill and knowledge. I think if you ever do plan to release an updated version of this game, you should focus hard on removing the superfluous and unneeded aspects of the game, and focus on the fun bits. There is a good core here, it just needs a lot of polishing.