The overall design of the city is pretty good and the characters certainly do have certain charm added to them. The classic riddle is pretty easy to finish, so something to spice it up a little bit would be really appreciated, but due to the time restraint it's pretty understandable.
The only major problem I had with the game is that my mouse cursor didn't lock in the playing window. Not sure if that's a fault of the game or my browser, but it's certainly something that really discouraged me from playing, so after finishing the riddle I didn't even bother with finding the dog.
Overall, not bad, I really dig the design of city and characters and with little more polish and maybe more stuff to do it would be an enjoyable fun little game.