Pretty good concept for a game
I like how you design such a simple and easy mini-game in a day :)
I think you can add some life counter on the bottom.
Also the graphics can improve a bit, but if it is made in one day. I think it is acceptable.
You can also add in some effect after hittest with the smile blocks, such as a ripple with glow yellow filter. Something like that, but overall a pretty good mini-game for killing boredom XD