I downloaded this three-part zombie RPG somewhere in 2015 or 2016. No idea how old it could have been. It was in 2D, probably made with RPG Maker, and I think I downloaded it on itch.io, so likely an indie. I played it on Windows 7.
It was split in three downloadable files, two of them being additional content rather then the "main" game, and that each was about 1Gb in size, which I found pretty heavy at the time.
I don't remember much about the story, I feel like the basic plot was the usual "some zombie event led to the world being post-apocalyptic". What I remember the most about it was that the game opened by saying it was not a combat-oriented game and that should you be faced with a zombie or other for, it would be wiser to run away. Being used to adventure JRPGs, I did the exact opposite and (unsurprisingly) died pretty early on.
The game's inventory included a weight system. The game was seen from top down, and had a mostly dark green/black color scheme. I didn't go very far into the game, probably because I was looking for something more action-packed, but I think the map only contained a single city, and the occasional cellar/underground. IIRC the fighting was turn-based, but there were no random encounters, the mobs were roaming the environment, chasing you when they could. This may however have been different later on, in the part of the game I did not reach.
I tried browsing itch.io with the "RPG Maker" engine filter, as well as various tags (Horror, Zombies, 2D, Post-Apocalyptic...) but so far nothing came up.
What it's not (from comments suggestions):