You can use the cheat code
Player.RifleMagazine = (whatever number between 10 and 100k)
And you can spray the bosses orb, using crouch helps when it shoots
And then continuesly spray the 2nd phase, dodge the lightning
Viewing post in Syahata's bad day(v1.0.5) comments
You can use the cheat codes once you obtain the items,to do so though you have to go to your menu and click / tap on her head, and you can use these codes
Player.RifleMagazine = (10 through 100k)
Player.PistolMagazine = (10 through 100k)
C 0 ( paid version / 1.0.1 ver)
Also to kill the plant, the branch that shoots the poison orbs is what you shoot during the boss fight, then just spray the second phase with rifle