This guide includes END OF DLC SPOILERS . Please be careful when reading!
The final obstacle is your good old friend, Imaginary Barry, who appears to have grown jealous of your relationship with Zane. The final encounter occurs on Diver’s Isle as you attempt to access Bird Leg Cabin. Barry sends several familiar faces after you (Hartman and the Anderson brothers) who you must defeat in turn, before fighting Barry several times. These encounters play out similarly, and each enemy is accompanied by a wave of birds, which I would advise you deal with first. There are plenty of ammo crates around to help you along the way. Refer to the ‘Iron Will’ achievement guide for tips on how to survive without dropping to a low health state. This achievement, and Iron Will if you did well enough, will pop up before entering the cabin after defeating the final Barry.