I have a couple of problems with this game. There is no difficulty, there is no point in the letters, the levels are as easy as they could be, the background is nothing special and you say "Credit to the author of the music" but you don't even mention him once. Don't let this discourage you, let this be a lesson. This is a great start to making games but this is a game you don't upload and expect good reviews. You need to learn to pace yourself, not make 8 levels and barely any gameplay and go and upload it, take it easy during the development hours. Look at the game and see how you could make it better, for example: Make more levels, make him jump higher and make larger gaps. Use the letter function to make a cool game mechanic, create a new and better background. Just make it all around better. I KNOW you can do it! You just need the patience and willpower.
This was a great attempt, but it's not going to cut it in the real world. Like I said spend more time creating than uploading. Take long looks at the game and change whatever needs to be changed.