Unturned

The graphics aren't amazing. Rather, they're simple and don't pretend to be otherwise, and their relative simplicity and the colorful nature of the game help to contribute to that DayZ-reverse-aged-until-it's-a-primary-schooler vibe it tends to give off. Zombies have a variety of clownish and normal faces, just like the players. Darkness is dark enough to matter without being completely unmanagable and daylight is a welcome sight. Like many other survival games, low health tends to give you a heavy desaturated effect and there's nothing like the relief of suddenly being restored to color by horking down a few bottles of advil. Like many other voxel games, some of the features can be poorly optomized: I wouldn't turn foliage off of its default setting, for example, unless you're not playing on a potato like mine, if you value your framerate.
The zombies, unlike in many games, are faster than you unless you sprint. Also unlike you, they can jump and move without running out of stamina. I'm not sure the decision for the moment to have jumping take 10 stamina is the best, but it does serve to force you to carefully strategize when and where to use your precious yellow lightning bar. Zombies will only slowly catch up, so it's possible to run halfway down and then let it regenerate before having to run again.
Melee in this game is a little weird. The voxel engine means you'd better be facing your target directly at all times to get a good amount of depth perception, and like many other zombie games where you can move and attack at the same time, any situation can be greatly improved by your good friend the 's' key. Backing up and smashing in the necrotic conga line that's forming with your trusty fire axe is a frequently used tactic when you simply don't have enough bullets to deal with all of the little ♥♥♥♥♥♥♥♥♥♥♥. I wouldn't say it's a perfect system, fighting without a reach weapon - that is to say, fighting barehanded - will hardly ever go in your favor, but that's something of a given with zombies.
Ranged combat in this game is fast, smooth, and responsive. Unturned doesn't bother with realistic weapon sway or any such thing so it's very simple to just tap the skulls off of everyone in one of those aforementioned shuffling conga lines, and things feeling quick and responsive as they do doesn't hurt. Like Crysis, there's a button you can hold to quickly swap attachments, ammo types, and that sort of thing - quickly changing your battle rifle from a 6X scoped weapon with a thick muzzle brake to a suppressed close quarters weapon with a tactical flashlight and holographic sight is fast and smooth, and shooting from the hip is feasible without making aiming down the sight valueless.
Inventory
Ah, grid inventory systems, the bane of my life. Unturned starts you off with 4 inventory slots, and you'd better like those 4 because that's all you get until you can find a little student's mustard yellow knapsack and shove cans of food into it. The inventory, being an inventory with limits, is probably the game's weakest point. Items are right clicked to be swapped with, mouse wheel doesn't scroll consistently and crafting can be buggy if you don't have spare inventory slots to work with. Once you get one of the larger travel packs, though, things become relatively painless, though it's equally annoying that you're required to level up your crafting before you can make inventory storage items and place them down.
Crafting in this game is a little iffy. Like many games in development, they haven't included a way to discover recipes within the game and unlike the much more serious and painful cousing 7 days to die, don't include any way to quickly recraft a well-used recipe. The amount of inventory space required to craft everything is high, so you'd better be prepared to throw lots of items on the ground until you've got some crates and then a chest or some lockers.
The worst part of these, and the only place it goes from klunky to downright bad, is in how reloading magazines happens. To reload a mag you craft it and a box of bullets together in your crafting menu, or two boxes if you've gotten your filthy hands on a military rifle. However, (and this may well be fixed soon) the crafting system that normally shunts a complete item into your inventory will happily recraft rounds into the same magazine, burning through boxes until you realize what's going on. Magazines take one slot each which means if you want a rifle and three mags there goes most of your inventory space.
Early Access is less of a problem here, as the development team is highly attentive to the playerbase and is constantly polling them and fixing bugs. Some people I know won't play a game at all if it's early access but this game is either the exception that proves the rule or the proof that the rule is invalid.
Multiplayer is easily integrated, what with single player simply being running a local game server and from what I've seen it's exactly what it should be. You can host your own server with ease, pick PVP or non, change the difficulty, specify if gear from other servers should cross over to yours, and pick between maps, though the only two choices right now is a small canadian island and an arena map. More maps are planned, as the game is only in its infancy.
The existence of a gold account system is possibly the single largest other complaint I've heard. Fortunately, it seems that the benefits are 80% cosmetic and 20% hanging out on a gold-only server. You get twice as many skin options as well as a slightly tweaked UI, and access to double-loot mode for people that hate survival games. The lack of influence this has on normal games is promising and a decent way to encourage donations for perks without making it so casual nonpaying players suffer for it.

Unturned The graphics aren't amazing. Rather, they're simple and don't pretend to be otherwise, and their relative simplicity and the colorful nature of the game help to contribute to that DayZ-reverse-aged-until-it's-a-primary-schooler vibe it tends to give off. Zombies have a variety of clownish and normal faces, just like the players. Darkness is dark enough to matter without being completely unmanagable and daylight is a welcome sight. Like many other survival games, low health tends to give you a heavy desaturated effect and there's nothing like the relief of suddenly being restored to color by horking down a few bottles of advil. Like many other voxel games, some of the features can be poorly optomized: I wouldn't turn foliage off of its default setting, for example, unless you're not playing on a potato like mine, if you value your framerate. The zombies, unlike in many games, are faster than you unless you sprint. Also unlike you, they can jump and move without running out of stamina. I'm not sure the decision for the moment to have jumping take 10 stamina is the best, but it does serve to force you to carefully strategize when and where to use your precious yellow lightning bar. Zombies will only slowly catch up, so it's possible to run halfway down and then let it regenerate before having to run again. Melee in this game is a little weird. The voxel engine means you'd better be facing your target directly at all times to get a good amount of depth perception, and like many other zombie games where you can move and attack at the same time, any situation can be greatly improved by your good friend the 's' key. Backing up and smashing in the necrotic conga line that's forming with your trusty fire axe is a frequently used tactic when you simply don't have enough bullets to deal with all of the little shitpirates. I wouldn't say it's a perfect system, fighting without a reach weapon - that is to say, fighting barehanded - will hardly ever go in your favor, but that's something of a given with zombies. Ranged combat in this game is fast, smooth, and responsive. Unturned doesn't bother with realistic weapon sway or any such thing so it's very simple to just tap the skulls off of everyone in one of those aforementioned shuffling conga lines, and things feeling quick and responsive as they do doesn't hurt. Like Crysis, there's a button you can hold to quickly swap attachments, ammo types, and that sort of thing - quickly changing your battle rifle from a 6X scoped weapon with a thick muzzle brake to a suppressed close quarters weapon with a tactical flashlight and holographic sight is fast and smooth, and shooting from the hip is feasible without making aiming down the sight valueless. Inventory Ah, grid inventory systems, the bane of my life. Unturned starts you off with 4 inventory slots, and you'd better like those 4 because that's all you get until you can find a little student's mustard yellow knapsack and shove cans of food into it. The inventory, being an inventory with limits, is probably the game's weakest point. Items are right clicked to be swapped with, mouse wheel doesn't scroll consistently and crafting can be buggy if you don't have spare inventory slots to work with. Once you get one of the larger travel packs, though, things become relatively painless, though it's equally annoying that you're required to level up your crafting before you can make inventory storage items and place them down. Crafting in this game is a little iffy. Like many games in development, they haven't included a way to discover recipes within the game and unlike the much more serious and painful cousing 7 days to die, don't include any way to quickly recraft a well-used recipe. The amount of inventory space required to craft everything is high, so you'd better be prepared to throw lots of items on the ground until you've got some crates and then a chest or some lockers. The worst part of these, and the only place it goes from klunky to downright bad, is in how reloading magazines happens. To reload a mag you craft it and a box of bullets together in your crafting menu, or two boxes if you've gotten your filthy hands on a military rifle. However, (and this may well be fixed soon) the crafting system that normally shunts a complete item into your inventory will happily recraft rounds into the same magazine, burning through boxes until you realize what's going on. Magazines take one slot each which means if you want a rifle and three mags there goes most of your inventory space. Early Access is less of a problem here, as the development team is highly attentive to the playerbase and is constantly polling them and fixing bugs. Some people I know won't play a game at all if it's early access but this game is either the exception that proves the rule or the proof that the rule is invalid. Multiplayer is easily integrated, what with single player simply being running a local game server and from what I've seen it's exactly what it should be. You can host your own server with ease, pick PVP or non, change the difficulty, specify if gear from other servers should cross over to yours, and pick between maps, though the only two choices right now is a small canadian island and an arena map. More maps are planned, as the game is only in its infancy. The existence of a gold account system is possibly the single largest other complaint I've heard. Fortunately, it seems that the benefits are 80% cosmetic and 20% hanging out on a gold-only server. You get twice as many skin options as well as a slightly tweaked UI, and access to double-loot mode for people that hate survival games. The lack of influence this has on normal games is promising and a decent way to encourage donations for perks without making it so casual nonpaying players suffer for it.