Some more comments, now I have had time to consider it, firstly there are a few levels where you can destroy all items in one click because the reticule fills the screen, this should be adjusted, the general difficulty curve is all over the place for the official levels and could do with shuffling around, perhaps a tooltip of some kind for each powerup to explain the upgrades better. Other than that an enjoyable game and the sandbox makes it stand out from the other chain reaction games.
Whist a height meter sounds like it would be great, it would make this game too easy, most of the boosters spawn at certain heights meaning that all you do is stay on those levels and you win. At the moment you have to guess that height.
Very enjoyable escape game, the trick to the servers is to count stars, using the server order. and the trick to the valves is to follow the cords that connect them. I dont want to give away the exact answers as that is no fun, but hope those hints help, walkthrough is here: http://www.playonlineflashgame.com/2011/09/edgestone-video.html