Double Gunning is a strong thing, money is at an all time high with not much to buy, so how about this! When you die, you lose your weapons (excluding the sword) and you have to pay for your weapons back in the weapon locker on the Ferry of the Damned.
All weapons cost $250 to purchase back. When you buy a new weapon skin, you get a free weapon use.
Also New Ammo Types:
Grog Bullets- Makes your enemies drunk
Incendiary Bullets- Sets your enemy on fire
Poison Bullets- Poisons the enemy
Kraken Bullets- Ink the enemies screen
Okay thats all the interesting things I can think of