So to emphasise my point even further let me add this:
In a game where they've ambitiously created possibilities for you to KILL enemies in a unique and fun way, they shouldn't throw in this pathetic "Oh! You can also not use all that cool stuff and play the good guy. In fact, if you decide to use the cool stuff, your ending will be bad or 'much darker'.". Apart from that, the text thoroughly mutilates and dismembers the immersion (How the fuck should my character know how it ends to act accordingly?). It's so dumb.