Your game is okay for a skill-game, but not very interesting. After a few levels I simply lost interest and looked for bugs.
And found one: A player could cheat your game fairly easy by clicking right.
That being said, I find it rather difficult to hit your "Next"-buttons, because you have to hit the text. I prefer buttons with a background.
Also you shouldn't use green and red. I'm not colorblind myself, but I can imagine it might be rather offsetting for someone who is. ("Stupid game: everything is red in red...")
Background-music and clean lines might be a good idea, too.