The weapons are, well... the exact same weapons you see every where else. A few pistols that go "pop pop". A bunch of SMGs/LMGs/ARs that spray bullets at whatever you point them at. A couple of shotguns, a couple of sniper rifles... blah-de-blah. Neither interesting, inventive or particularly satisfying to use. The only notable standout is the flamethrower.
Coupled with the dull weapons is a complete dearth of enemy variety. You have animals that try to bite you and guys in red shirts that try to shoot you. That's it. Bugger all variation in behaviour or abilities.
I was going to comment on the weapon stuff but people already said it's not sci-fi and there's enough variety as it is. The hell did you expect, A shrinker?
Enemy variety, that's highly overrated and again it's a game about pirates what did you want, zombie pirates? Human Torch pirates? The Hulk? Facehuggers?
I remember it being a normal game on the hardest difficulty setting, it's how it goes nowadays normal isn't normal anymore and this goes for every game.
Sam and the US agent were very fun characters, Buck was a good antagonist and playing Indiana Jones for him was an interesting quest, Hoyt is a majorly underrated son of a ***** considering he's the one who broke Vaas and then there's Citra the cult leading ***** and her dog the Liberian guy, overall it's a stronger cast than most games have. The friends weren't very deep but did they need to be? What did you want? A massive prologue that would disinterest most people, a codex database or maybe a few hours of carefree conversation while everyone's in mortal danger? Don't think it would make much sense at all.
5) Fucking hell the main character and his friends are completely unlikable. Are you telling me this dude can rush into a town, shoot 15 pirates in the head and plant a bomb, but the moment he has to skin an animal he collapses into a tearful mess? Fuck that.
To be fair, it's one thing gunning down a random pirate trying to kill you it's somewhat easy to rationalize and not that brutal when you think about it... Try skinning him, that's a gruesome lengthy process, have you ever tried or seem it in an animal? Still gruesome especially nowadays when we get everything at supermarkets.