This was a fun little puzzler. The interface and UI are spot-on, graphics were nice, loved the music a lot, and the sound effects suited the game style.
I kicked off with normal, and ran out of time the first time - second time I discovered the light button (had tried to click the lantern icon), then cleared it the third time.
Hard mode was another matter :) After several attempts I had a strange moment of clarity and cleared it without a single mistake..! I imagine the game could be broken by use of print-screen, but I'm not sure what defense mechanism you could use - the best one probably being 'you're only cheating yourself'! Perhaps having the sparkles display on alternate frames so it's impossible to get everything in a single screenshot.
You should expand this I think. It's a tight little puzzler and would probably suit mobile well (at least cheating could be mitigated more easily there)