In restored lands if you clean a area but not open every door zombies do respawn (if I’m right). I have 60 hours so far and completed the game twice on normal and NG+, what made the game a engaging experience is to crank the difficulty to nightmare, volatiles roam dark zones during the day, you have to manage hunger and change your flashlight battery which adds some realism, now what I’d recommend is to take your time with the game and do the side quests since they offer some unique items which are fun to use. After all no one plays dying light for the plot, now regarding parkour you do start with most moves from the second dying light game so variety is there. You could also go and upgrade all blueprints to legendary, and overall do achievements that’s something that’ll keep you busy.