7 Days to Die is a voxel based survival horror game that focuses on crafting and world building, all while having you take a hand at surviving in an undead filled post-apocalyptic world.
Pro The conditions of the scenario can be changed
If the current scenario that has been created is discovered to be too easy or too hard, or not enough loot is being dropped, the next time it is loaded up, there are options to change the settings, such as difficulty, zombie spawn rate, loot drops as well as others.
Pro Constant sense of vulnerability, which keeps the player alert and on edge the whole time
As the player makes progress in the game by interacting with the environment, killing zombies or building things, they are rewarded with skill points that can be used to unlock new skills such as combat strength, higher stamina or new crafting options.
But even though the skill system can seemingly make the game easier, the severity and size of the zombie hordes will keep increasing with the time spent in game and the progress made by the player, keeping them on the edge and making them feel a constant pressure that an attack may come at any time and that they should be prepared.
Pro Great replayability
No matter how many times you start a new game (random gen) you will never get the same experience. The crafting is the same, enemies are the same, game mechanics are the same but the gameplay is not. If you add the mods available for this game then you will have a whole new experience with added/altered crafting, different enemies, more quests etc...
Pro What you build is not only for creativity, but also for gameplay purposes
In 7DTD players don't build their homes only as bases or places to sleep in, or build cool looking things just for the fun of it and to test their skills.
Every 7 days, a large horde of zombies will attack the player wherever he or she is, trying to destroy them and what stands in the way of the player and the horde. This is why the player needs to think about how to build traps that will help them kill a lot of zombies and how to make a strong enough house that will not be destroyed easily.
Pro Randomly generated open worlds makes for a ton of replayability, as each playthrough is never the same
Recently added in the Alpha 9 release, randomly generated worlds allow the player a new play experience every time they open up the game. This means every server will have a different dynamic based on their layout of the world.
Pro Single, co-op, and multiplayer gameplay modes give plenty of choice as to how one would like to tackle the game
Three different play modes including solo, with friends, or competitively over the internet gives a lot of choice as to how someone would like to play the game. Be it with friends or solo, the options are there.
Con Can be frustrating at times
This con is a bit dependent on RNG. Your character might end up starting in the middle of the snowy mountains with no clothes or the desert with no water, making it hard to survive at the start. Other times the area could be resource poor, making it hard to build a base and tools and weapons. Or, you could end up spawning in an area filled with some of the hardest zombies in the game with no weapons and poor fighting stats.
Con Sometimes there will be a fog that never goes away
The weather in 7 Days to Die can change, adding a nice touch of realism. Typically, foggy weather will occur close to every 7 days, which is when a zombie swarm will hunt you down. Sometimes though, this fog doesn't go away for the rest of the game, leaving reduce visibility, even more so at night with rain and fog.
Con Randomly generated open worlds has no generation options
Randomly gen has no option to customize how it is generated (like in minecraft for example) and could make it quite problematic if you want to have a good map, as there is no way to know how good or bad the map will be. Random gen also make unrealistic hills and road that almost go up/down vertically with vehicle spawning in such way they seems to be floating.