SO, this is the trick used during development to advance as far as possible without dying. What you need to do is kick repeatedly. There are two key combinations that result in the flying kick. With the most reliable one you can Jump and press the arrow Left or Right key, which results in a flying kick.
The flying kick produces higher points and is more impervious to counter attack. If you do it repeatedly you can get to level three or so. You might even get further.