I played it for about 20 hours, which for me took several weeks. I enjoyed it, but mostly played in the daytime unless something particular required me to go out at night. I like my zombies like I like my coffee, slow and defenseless against me.
When Dying Light 2 was promoted as having hundreds of hours of content, that was just a big turn off for me. Having said that, once it has been out for a couple years and I can pick it up for $10 like I did the first dying light, I wouldn't be against buying it and playing for the first 20 hours.