Edit: this for example was a really good fight - the game has its moments...
The only good thing about that fight is the giant monster which is completely wasted. Giants boss fights always look better because of size difference but this is an example of everything that's bad about it.
You can go two routes when designing giant boss fight.
First is realistic, what I call tactical way. With such approach there is no way you'd shoot weak ass lasers for fifteen minutes at immovable monster until you drop its HP to the ground (HP bar and realism don't go well together). What you'd do if this was real life situation. Mostly lose because that monster would try to crush you, unless it is trying to intimidate you, for you to leave it alone. In that case most sensible would be to avoid the creature. If you must annihilate it, then you'll need some serious firepower. Missile launchers, mini nukes, good old Japanese mecha suit to fight it on equal terms.
If you want stylish, less realistic battle then you'll fly around it with your crew, chop at it from different angles trying to immobilize it by severing important connections on its large body. You know, like that Mickey Mouse versus giant cartoon. Or like in most cartoons and anime where few little ones are fighting huge monster (Attack on Titan comes to mind). But in order to do that you need to be able to freely fly around with a jetpack, to employ adequate weaponry for said fight, to communicate and give orders to smart AI. None of that is possible in this game from what I've seen.
Edit: Exactly the same boss fight you get at the end of Borderlands. Shoot at tentacles until they lose HP then magically explode, leaving monster vulnerable to regular attacks. This shit exist since arcade shooters. I must say Borderlands was good up at that point, didn't like it as much after that boss fight. Only boss that left worse taste after I finished the game is that one in Risen at the very end. That was Nintendo grade boss fight with moving platforms and shit.
