841st Dungeon Grandmaster here, my advice, as others already suggested, is to prioritize cantrips (seven of them would be advisable) and shields (at least 5, I had 6 in my lucky run), don't mind if they overlap on a single piece, sometimes drawing a fully upgraded pawn or queen can be the best thing happening to you today. Cheers to J4NW for the wonderful work.
Bloody insane but finally I did it.
Best advices I can give you are: power extender, static field and extra clips are your best friends like the rocket launcher and the holy grail. Try to pick up Rapid fire and Invincibility before going into battle because it will make it a lot easier. Last but not least stick yourself to the ass of the raze soldier and try to kill him or make him commit suicide rather than killing the other humans because later on the level it will be more difficult to spot him.
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