Hi.I had to play one game when I was a child but I don't remember the name.I this game I'm a boy with blue helmet and blue suit.Some of the enemies in level 1 were clowns.The boy was killing them by kicking some ping pongs.When enemy hits you, the suit color was changing and then you start shoot two ping pongs.After another hit you are shooting footballs.
These are all the things I remember.Hope you'll help me.
Thanks in advance!

Lol, at first I was thinking Mega Man, but then I remember the game you are thinking about.

It's called Doki! Doki! Yuuenchi or English title is The Trolls in Crazyland.

Here is gameplay, I'm pretty sure it's the game you are looking for, but check it:
http://www.youtube.com/watch?v=pf9-BkCoBQk ;