Immortal Redneck

OH. MY. GOD.
TURN OFF AUTO WEAPON PICKUP. Sorry not sorry (replace weapon scroll) ALSO steals your chance.
Took me 5 tries. Nothing made me want to invalidate my life quite like Redneck hitting F7 just to spawn a CROWBAR final boss. But, I digress;

Depending on your skill with *all* of the ingame weapons, I'd highly suggest;
*Redneck, for faster shots
*Neith, as Falcon gives some protection from RNG/Far shooters
*Apis. His invulnerably came in handy when slow weapons mixed with full rooms. His rolling kunai endgame didn't matter, either, 665 final health and 412 attack won the day.

You are also going to want to bulk up at least both health and attack in your skill tree. Defense helps but attack is a must. Roll dynamite, crowbar, single shot anything? You better hit like a tank.

As mentioned above, weapon swapping of any kind, even throwing and picking up your gun, makes this impossible. This makes picking up scrolls a form of playing with fire, so I spent 40k on gold scrolls and ignored what I found.

Hard, very hard, yet doable.
Happy hunting (>*_*)>