Well, you asked for feedback:
* Gold is difficult to see (actually, every text is difficult to see. They blend on the background. Try adding a "box" with half transparency?).
* (EDIT: And if you add a box, I might report adding a white box below white text like on Changelog will only make the issue worse >.<)
* Game tries to force itself to be played fullscreen (this is really intrusive and should be avoided)
* Achievements are really strange... I can't say they work.
* Browser says the game is reproducing audio but I hear nothing?
* It is a bit... unusual, for an idle game be timed.
* The game description (on NG page) said: “Collect gold to restore your kingdom before the dragon takes it all away!”. For some reason, I'm have a feeling it did not delivered what I was expecting from the propaganda.
* What exactly are the objectives? When do you win? What you need to do? How you get Skill Points? How do you lose? How much damage the dragon causes? What the skill icons are for? And please don't add the description as a hover text - The game is timed, so player probably won't spend their time addressing that.
Lots of potential, but also, lots of design issues.
Good luck in improving the game ;-)