750g can be gotten in playthrough one, couple of cheivo's are missable,
What Are They Worth? 150g
Acquire all of the bottle caps in the game.
Nothing hard here just play the shooting galleries
A Terrifying Assassin 150g
Turn the tables on Verdugo, the right hand of Salazar.
Instead of dodging this battle just kill him/it
Do Not Shoot the Water! 50g
Summon the master of the lake. Don't rock the boat.
Just shoot the water before you get in the boat
Playthrough two is with Ashley, if i remember from PS2 she has no weapons

(apart from her personal bazookas.....sorry)
Playthrough three on professional(unlocks after playthrough one), If i remember i am sure you get a infinite ammo gun(Chicago typewriter), but not sure
I would say on normal its a 6/10 for difficulty, the controls do not help but as i said earlier they do come to you with time