Got to essentially invincible loadout with freezing sprinkler, shotgun max range, and freezing grenade launcher. For the eye select "attract pickups when eye is at tower", extra drops upgrade, and higher pickup radius. Avoid picking boomers, choose some hulks at the beginning of the run so you can leave your tower and collect powerups when needed, you can kite those hulks away from the tower. Eventually I got to a point where nothing could get through, so I selected weirdos every time I could to max enemy drops (they have a lot of drops and they drop them close to your reach without charging all the way in). No need to dodge the Be Not Afraid boss, its damage doesnt seem to scale so just tank their hits. You eventually become invincible with this strat, I only died because I got bored and wanted to use my points.