Great job. This game is simple, elegant and minimalistic. This is something anyone can come in and play. There are not many mechanics to learn, yet such mechanics are expanded nicely into the stage design of the game.
I got a few complains though - one minor and one major:
Minor: I wasn't aware that I have to collect all the coins. After I saw the timer, I was like "Holy shit... OUT NOW!", and went out, collect some coins on the way. I ended up ignoring coins in harder to reach places and thought I have to go back to the beginning. Only to realize nothing happen. Fortunately, there is still time, so I ended up going back to grab the remaining... was it 12 coins? And got 2 mins left. The timer is quite generous there.
Major : MAN! Why do you have to put "'M' to mute" text on bottom right? You got yourself awesome 8 bits music here. Which human being would dare muting the music! That would be a sacrilege! :)
Yep. Keep up the good work. ;)