You're 20 hours in and you still haven't unlocked fast travel? That's pretty slow (I just finished endings 3-5 last night and I'm at like 30-35, even with a fair amount of sidequesting slowing that down), but you're probably at least close (you get it a short while after the Amusement Park). That should help, particularly where the story grows quite a bit from there (you've barely scratched the surface of it before then, aside from vaguely hinting at the core themes).
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