HTML5Test doesn't pay too much attention to stuff like SVG, which is Opera's strong point. One area where opera is lagging behind is webGL support and that reflects on the tests.

SVG is not HTML5…

That site isn't very useful since it only reflects what the author thinks is important. It doesn't show actual standards compliance. He chooses tests and assigns scores according to his own priorities. So it's misleading to call it "html5test."

Scores are based on the number of features supported. What's wrong about it?

What's wrong is that one feature gets one score, and another feature gets a much higher score. Scores are not based on the number of supported features, but on higher scores for certain features.

What are you talking about? One feature is one point.