I agree with some of the other commentators that the final boss is fairly poorly constructed. Considering that it is possible for it to continuously use its laser it can take almost half your fuel to even get the chance to bounce into the weakspot.
Possibly by changing the randomness to be somewhat more evenly distributed would reward strategy and skill instead of being a toss-up based on getting a good random distribution of missles:lasers at the beginning of the stage.
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