For me, I get pretty far in the game by doing the following:
- when in a screen with many enemies / rocks, I use the flamer + shield early on to destroy as many enemies / rocks as possible, then clean up the rest with a longer range weapon. This will require some shield bonus hunting (either that or extra life bonusses...)
- when moving around, I always try to get back to the center when I'm done collecting a bonus, because there the rocks give you the least surprise when appearing from the side of the screen.
- each boss has a specific trick to beat it (the first one is pretty easy, you have to find a spot close to the hull where he can't hit you, but you can hit him AFAICR).
- in the tunnel sequences, I try to stay at the bottom as much as possible, because then your ship is not blocking the view so much. Move up and immediately down again when a rock is flying in low. I never shoot in the tunnel, it seems pointless. The rocks take ages to blow up. When you enter that "MUST... KILL... EVIL... ROCK!" mode you'll only end up crashing into it.
- I tought myself to activate the shield automatically when my brain goes into "OMG! OMG! WHAT DO I DO? WHERE DO I GO?" mode. This is a HUGE help.
I love Stardust, it has a great soundtrack and it can actually nail you to the edge of your seat (or to the ceiling, when your butt keeps getting kicked by rocks).