Sorry, I much prefer the original
This was well put-together - the title screen and "game over" message were nice and polished. And it worked well enough, I suppose, but it lacked the feeling of steadily increasing challenge that SF cave has as the walls gradually close in on you. Still, it's a good idea trying to take this sort of game in a different direction... I'd suggest taking it in a wildly different direction - perhaps have a number of tunnels and allow vertical scrolling.