New Game+ on H:ZD is quite easy because you have all the gear, notably blastwires for early game scrappers and chargers, the war bow for anything with a cannister kill option, and the Banuk hunter bow for DPS on frozen enemies. You also have shield weaver and huge health, which makes random death very unlikely. Playing the regular game on Ultra Hard is a whole different story. Everything kills you in one hit until you're about level 20, and then 2 hits until you're level 40. It takes ages to get heavy armour and shadow weapons because everything is colossally expensive so you're not optimally equipped. And most enemies have so much health that even after blowing off their canisters they're still alive.
Aloy, my #1 waifu, ready to fuck shit up |