I'll give you some tips to get you through the first 2 levels. One great tip is that there is a hidden fairy in level one. There is a bush on the right side of the screen immediately before the stream. Shoot this bush to rescue the fairy. When you die, the fairy will grant you some of your power-ups back. I'm sure there are hidden fairies in the other levels, but I haven't found them. As far as the bosses go, I use the blue laser on the level one boss and the machine gun on the level two boss. This makes your job a lot easier. For the level one boss, get real close to him while blasting your laser before he is fully rendered on the screen; this should obliterate him before he even gets to fire on you. The level two boss just requires some fancy bullet/kamikaze plane dodging along with a large spread machine gun. There is not much advice I can give you for the latter levels; they start to get hard starting with the level three boss, who is a chore to beat. With a little practice, you'll find yourself progressing further and further into the game. good luck!