PZ is a great game that thankfully is available for linux! It is constantly adding more complexity, but not necessarily more hassles. I love the fact that it is a range of difficulty and supports different players with different game styles (from kill them all action types to open world long-term survival with trapping and farming in the zombie world). I have not tried multiplayer but even without trying that it is providing a lot of fun, challenge, and variety.
This game is so good as is. It has sooo much more promise if they achieve half of what they have said they would. Mods are heavily recommended though which might be a con for some. Not a game you can play constantly, but a ton of fun to play for a month or two, leave for a few months, then come back and learn something new all over again. Plus, updates are slow to come, but they are pretty good. They really need to add NPCs though. A literal game changer when that happens. If you like zombie games, this is one of the best sims for the zombie apocalypse. My zombie fix usually is a rotation of this game and State of Decay 2.
The core idea, survival aspects and resource management are great and make for a really nice game. The issue is that once you settle down, there isn't all that much to do. Exploration for food and water becomes trivial, and the only risks are the ones you take.
The best way to enjoy PZ is to play multiplayer with friends so that you can either bash each other's brains out or aim for a mutual long-term goal to keep you occupied.
Easy to start playing, complex to master. Fun mechanics that will have you counting the hours to play again.
Isometric view, satisfying zombie killing and explore&loot mechanics.
Well worth the <20€ it costs. This is a must.
Project Zomboid is a true indie game, and you can feel it in its every aspect; its a game that can give you hundreds of hours of entertainment. Although it has been in developing for a decade, and still is, the game is fully playable to the point that you won't need any other game to sink hours if you like it.
So not only you can already play it for hours, but there is the certainty that is gonna get better with further development, as the devs insert even more content into it.
Best thing of the game for me is the customization: you can modify the game settings, you can configure your own game as you like: fast/slow walkers; supplies; spawns; weather; everything. There is no wrong way to play the game, you can make it as you like it to be. That also gives you a lot of flavour, since you can make one game completely different from another. You can play pure survival with no zombies; walking dead settings; 28-days settings. Whatever you desire.
Tragically the customization dies here with GoG. There are no mods you can use. Its not that you will need them, because you wont. But if you wanna go one more step, you cant. Unless you get it on Steam, since the modding community has settled there (there's no Nexus nor ModDB for this im afraid). So if you like modding or using mods in general i recommend Steam over Gog, sadly.
In summary: if you got as far as to read this, its a no brainer. Buy the game and enjoy.