There obviously wasn't put a lot of thought into the game. The game is unbelievably easy. If you just go for health, blood fangs and health from vehicles then you have won the game just by flying along the surface and nothing else. Going for the opposite wins the game equally as easy, possibly a little faster, but you don't regenerate health fast enough to survive sandbox.
People who don't discover this is properly gonna have a good time though, but personally I think the game itself gets a bit boring after just a few minutes.
At the end I ended up having the worm's head literally fill the entire screen and god knows how long the blood fangs were. I could take down jumbo jets and cows at the same time and bombers didn't even get a chance to drop their bombs before they were torn apart and converted to health. At this point enemies didn't even spawn fast enough to sustain a combo over 100, either because of lag or because I was moving so fast.
I think the only fun thing about this game is how high you bother to rack up the points before you get bored.