How to defeat the Bosses:
Boss stage 1-2:
1) shoot at middle (top part) of boss while entering
2) boss begins to shoot from two laser cannons in straight line, stay a little below so you can still shoot at top part of boss, boss will go up pointing at center of screen you should go down. Then boss will go up shooting at center of screen, stay down.
3) boss will turn showing the bottom, it has two missile launchers, just stay at straight line and shoot one until is destroyed while destroying it's missiles, and then the other. you can destroy missiles by shooting at them too.
4) boss whil turn again and begins a circle motion always pointing at center of screen, here you should be up shooting it's right wing, following ahead the boss circle motion.
5) the boss stays static, watch out as it is charging plasma, shoot at middle until you see the charge.
6) when boss shoots two plasmas, go all the way up otherwiase the boss will collide with you and taking a lot of shield or hull.
Repeat.