Thank you, I really appreaciate the feedback!
At first, this was supposed to be a really short game with a far different ending and less weird stuff. Then, it became some sort of demo/teaser for a bigger story. I even considered releasing the full game (and not different chapters), but I had never made an episodic game before, so I wanted to try that.
The reason why it feels so linear is because it serves as a prologue and, for the sake of the story (and in order to avoid big spoilers), there couldn't be much variation in terms of story.
In hindsight, I should have added more stuff that didn't interfere with the story, but since it's too late for this chapter, Chapter 2 will have more exploration, choices, etc.