Ruiner

After you beat the game for the first time you will unlock New Game + run, this will allow you to keep all your upgrades for this run.

New Game+ difficult is HARDER than HARD mode, but don't worry, this isn't as bad as it sound, you only need to be patient and remember how the enemies act, especially the bosses (Like Nerve and King).

I suggest you to over-use the Supply Drop ability to spawn a handed weapon (like Vis Carver, Fire starter or Armor Breaker) to use it with Power Attack, as this combo is stronger enough to take down the big ones. You'll maybe want to use Overload with a weapon like AT Fusion MAX to take out enemies like the angels and Mother fast.

And Dash, a lot, this is a great place to unlock the 'Over 9000' achievement.

Finishing the game on NG+ will also unlock the achievements for Hard, Normal and Easy difficult, depending on which you don't have. So, you maybe want to start a New Game on Normal or Easy difficult to enjoy the game or conform the controlls.

On your first try this could take around 6 hours. Good luck.

Just finished this in a couple hours and wanted to share my method. I found this a lot easier than Hard, dying only 6 times in this mode versus 106 times in Hard mode, and 5 of those times were me accidentally dropping a Supply Drop on myself.

For the whole run I used maxed out Energy Shield, Reflex Booster, Dash, Use of Weapons, and Resource Optimizer. By the end I had added Supply Drop, Power Attack, and Grid Converter. Could probably swap out Reflex Booster for Power Attack and Supply Drop at the beginning.

My strategy was basic: Energy Shield + Dash with a strong melee weapon from Supply Drop (personal favorite is Vis Carver). That got me through the whole game except the Twin Sisters, where I traded Energy Shield for Overload. Dashing into an enemy with the shield up, if it doesn't kill them outright, which it will with a lot, will stun them and give you plenty of time to finish them with a melee hit. For all the arena fights I basically dashed around the level with the shield up sending enemies flying everywhere. This also works on bosses; Shield, Dash, stun, melee charge attack, back off, rinse and repeat. You can also time Supply Drops to fall on bosses while stunned, dealing a good chunk of damage; this was especially useful in the TrafficKing first fight, which gave me the most trouble in Hard.

And that's it. 3 or so hours, 6 deaths (5 self-inflicted), and 100 GS in the bag.