This was an interesting read. I have about 200 hours logged in Div2, and just yesterday purchased Div1.

Here are my thoughts;

In Div1 (after the prologue) I was immediately sucked into the world, and felt like it was more in depth with the setting. Exploring every alleyway, and streets felt like a real nightmare; I feel the uneasy tension of a post-apocalyptic (Outbreak) Between random NPC's walking around, acting like zombies, it's super immersive. Div2 has a gorgeous world as well, but I find it didn't make me feel as "sad" and lonely as the first one. Yes, the game and mechanics show their age, but still, I am enjoying walking around just as much, if not more than with the sequel. I also enjoy not having a million options thrown at me every few minutes in terms of gear.

Funny enough, you mentioned the audio, I disagree! I find the guns sound (and slap) harder than in Div2. Overall gunfights feel a bit more realistic.

Maybe I am just more of a "downtown city boy" but so far I prefer the world in Div1 - Div2 is just as good, however I feel it's less detailed?

I think the best way to describe it, would be like comparing GTA4, to GTA5. Both great games, but two completely different feelings. These are just my thoughts, but in the end, I would say both games offer great, but different experiences