I never played the original Zombicide games. I don't know what exactly led to that decision, but I had a general awareness of their existence and in my head I wrote them off as these big bulky games of dice rolling and moving around the board...not at all my cup of tea. It got to the point where Zombicide was 3 seasons in and every time I saw another copy, edition, expansion I didn't even mentally register that it was a game I could hypothetically play. I felt similarly about any of these games. Earth Reborn, Gears of War, Doom, etc. If it had minis I was already halfway out the door before I judged it on any merits or lack thereof.
I don't know why I had this mindset to begin with. My best guess is that I grew to love games through seeing the elegance of a good gaming system. I went from roll and moves like Monopoly and roll to win games like Risk, to games of Stone Age, 7 Wonders and Castles of Burgundy. I resented games like Warhammer that I had long ago played, for the tedious amount of prepping and homework like movement/aiming/attack and defense grids, all backed up by the luck of dice rolling. At the same time I had fond memories of Magic the Gathering and the cardplay and mechanics that drove the system. Perhaps in my head all this background noise contributed to the idea of a game with minis and dice as a waste of my time? I'm not really sure but perhaps.
Likewise I can only guess as to why I finally changed that attitude. I think playing games like Blood Rage and Rising Sun certainly helped. Elegant games with no dice rolling, yet still amazing minis and amazing experiences. That introduced me to CMON games which can become a rabbit hole in and of itself. I don't remember exactly when I decided to try Zombicide but when I finally did, it was with Black Plague, a generally well acknowledged improvement over an already well received game.
Wow I've been missing out. I spent enough time going through the history of how I came to avoid and play this game that I'll keep this short. Zombicide will never replace any sort of high strategy game in my collection....but boy is it fun. Ultimately you and your friends handle 6 survivors between you, and then you need to complete the mission objective. While those vary, the basic gameplay is always the same. Find better equipment, level up your characters and abilities, and do it all before the zombies overwhelm you and stop you from completing objectives. Along the way you'll slaughter hordes of zombies, and have epic moments where you narrowly escape death or slaughter a massive grouping of snarling corpse eaters with a well planned dose of dragon bile.
If you haven't given a Zombicide game a shot yet, I highly recommend it. Sometimes you don't want to crunch numbers until 2 am...but slaughtering hordes of zombies is fun no matter what time it is.