Not a bad start if flawed
The theme, though a bit old hat is pleasing enough and doesn't distract from the core mechanics of the game, though it doesn't add that much either, at least not in the early levels (more on this later). The mechanic of tracing chains of similar tiles is different enough from many other match 3 games to be enjoyable, and the addition of special tiles does add some depth and makes me want to get past level 8 or so.
However the combination of timed levels, random tile distribution, and no level retry results in the player being defeated by pure chance and forced to restart the game from level one on a regular basis. I this weren't punishment enough the tutorial pop-ups insist that I attend to them even when I've seen them a dozen times. I thought maybe that the ability to complete a level by matching enough chains might help me when I've run out of shuffles and the correct tile just isn't falling into either channel next to the lock, but after playing this game from level 1 20 times or so I have yet to finish a level by this method. Maybe it's due to my lack of skill at the game, playing as I am on a laptop track pad, but I have no idea as there is insufficient feedback to tell me precisely how far away I am from matching enough tiles; does the key need to cross the line, or maybe meet the lock in the little track on the left?
As the title says, this isn't a bad start it just needs a few things tweaking. As other reviewers have said, maybe a system of lives (with a way of earning more through skilled play perhaps) would make this game really enjoyable rather than amusing but ultimately frustrating.