As I have said, it's based on my opinions...
The reason that the chain gun feels weaker for me is that its just like the single shot vulcan, only on rapid fire, and you know how hard it is to get close enough to enemies to actually hit them. In this sense, in comparison with the other weapons, then you'll see that other weapons has a better hitting capabilities.
Well, don't lose all your lives... simple really if you are very observant and cautious.
Think about this... Contra, Super Mario, Megaman, what do they all have in common apart from being platformers or shooters, or mix of both? They all have a life system... and as expected, lose all lives and its game over. Games of today cater too much for convenience that the enjoyable parts of the classics are forgotten. The lives system makes you better actually. Understanding what and how it killed you and find a way not to get killed the same way.
Ok, so you based your opinions on somebody else's, rather than actually internalizing and creating an even better understanding of that opinion?
Also, the stats for the Destroyer are good, it's only because you can't use it properly, doesn't mean it sucks. Don't expect the game to work for you, as is with the ships themselves. There's what people would call "BALANCE".
Those are my opinioned ratings at what I feel about them... at most, they're not as good until they get to lvl 3 and above, so if you like a weapon very much, get it to lvl 3.