• Bunches of Bananas
  
• The Shield
  
• Extra Grenade Ammo
  
• A lot of ammo for your weapon of choice

If you don't already know how to use the bananacopter glitch, I will send you to this guide:
https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=938075925

• Directly after entering equip the Bunches of Bananas and the Shield
  
• Turn the camera around 180 degrees and notice the small perch with the button
  
• Bananacopter your way up there
  
• Once up, feel free to turn around
  
• Shoot down with whatever you can or want, nothing besides Marie fires any form of Grenade
  
• Some enemies can't hit you and remain in doorways. You don't need to come down. You can use small ledges either side of the balcony and fire off a grenade, which will scare them in to moving in to an open space
  
• Turrets are unable to fire above the legs, apparently, so feel free to just fire at them without consequence
  
• The Mini Tank will usually remain in the doorway without moving even with "encouragement" from Grenades, and if you shift along the ledges enough it will fire on you. I recommend jumping back and forth, in and out of view lobbing Sticky Grenades directly at it

Once all waves are over, Marie will be vulnerable. She CAN fire Grenades, so jump down before she forces you down. She only takes one hit to kill, so don't expect a big boss fight. Just a woman with a minigun.

That's literally it. It takes a few tries and it took me an hour to get it perfect and it can be rather slow at times, but it's easier than doing what you're supposed to do.