it was an old videogame. i played it in the early 2000s on Windows but it was probably made in the 80s. It was a 2d spaceship bullet hell game where you fought tougher bosses at each stage. the bosses were large spaceships comprised of different parts that you could blast off. However, the parts were chosen based on how you played: lasers if you didn't move much, stronger shields based on where you fired, or rotatable arms if you shot at its blind spot. It had basic pixel art that was mostly only black and white, but i remember some color in the lasers and flashing parts when they were damaged.
I think there was a skill tree for powering up your space ship but i can't remember.
It also had several play modes like 'only one life', time attack, and unlimited.

Any suggestions to what this game might be called would be appreciated.
thanks.