This is a really interesting game I have to say. At first I thought it would just be a simple shoot and kill the people, but actually going into their lives and showing how you end one world is really cool. I played and got both the dialogue endings, it's pretty cool that you did that.
I think if this is expanded upon it could definitely make for a good game, one with multiple endings where you can choose to spare or not spare the lives it opens up a lot of good possibilities for story telling. Really impressive job for your first game! Keep up the good work.