It is an MMO mix between Minecraft and DayZ because you have a large crafting menu that requires gathering resources and you must survive in the wilderness against starvation, injury, wolves, grizzlies, zombies and players who may choose to rob/murder you. It is 1st-person view only and no maps or vehicles are available yet.
You start out butt-naked with some torches, bandages and a rock. You are a man and there is a nudity censor that covers your penis and ♥♥♥♥, but this can be turned off via a multi-functional F1 command console just in case you are are fascinated with the male anatomy and want to stare at everyones junk, atleast until they craft clothing. There are no female characters.
Initially, you must use your rock to pound trees/wood piles to gather wood, SMALL boulders (Not the mountains) to gather stone, iron ore, sulphor ore,etc., and chickens, boars, elk, wolves and grizzlies to gather animal fat, raw meat (which must be cooked or else you face poisoning) and cloth, which can be crafted into clothing/leather and lead to better protection from the cold and attacks. There are radiation zones filled with zombies that carry very valuable loot. The zombies, wolves and grizzlies are very agile and persistant. Sometimes I find myself being chased for long distances and by all of them at once. I like to run around dangerous areas and get all of them chasing me at once and then run towards other players to either get them off my trail or get help from other players, who usually end up running and screaming as well unless they have guns and are friendly. You run just fast enough to stay one step ahead of them.
C130 cargo planes randomly fly over the map and drop very valuable cargo via parachutes. These contain items that take time to craft such as C4 explosives and assault rifles. Beware though, where there is a cargo drop there is sure to be a party going on because the servers are supporting 128-256 players as of now. The map is a huge. Some of it is unseeded. There are vast, heavily-forested valleys surrounded by mountains that you can climb if you have the patience and want to hide/build there. You wont be alone. The mounatins are actually rather nice and provide plenty of hiding places. One can only imagine what the map will look like once it is completely seeded. Believe me when I say you wont notice that some of the map is unseeded, it is huge and you will not find these unseeded areas easily until you trek through very long distances of forests and mountains. Unseeded simply means there are no mountains/structurs/creatures and fewer pine tress. You probably won't survive to see this underdeveloped land.
Unless you have a sleeping bag, you spawn in a random locatiion. Since there is no map yet, you must become familiar with your area. You can build a huge fortification or just a small house or shelter. Wood shelters despawn after 12 hours and all other wood structures after 5 days. Wiki doesnt say if its real time or game time, but I beleive its real-time. Players can break into your buildings with hatchets or C4 and then kill you in your sleep and take everything. The metal doors can be blown off with (2)C4's and the wood doors can be whacked 200 times with a metal hatchet, although, I seem to be able to do it with just over 100 hits. So you'll need to be strategic in its placing or be ready to defend it. I prefer to be a nomad and simply live in the mountains. Beware though, if you are found sleeping on the ground, which occurs when you log off, then you are fare prey.
A Word About Servers:
PVP means player versus player and you can be killed at any time by players and not just when you are found asleep. You may find yourself fat and happy full of gear and all of a sudden an unfriendly player decides to kill you. It can be very frustrating, but this is a survival simulation and you must play the part. Most players team up to help each other on PVP servers in order to survive. You'll find large gangs roaming around and raiding what they can. I would call PVP hardcore.
PVE means player versus environment and the only way another player can kill you is if you are found asleep and vulnerable. Otherwise, noob players will be baffled by their inabilty to injure you or read the server properly before hitting the join button. I highly recommend you start with PVE servers since it gives you a great chance to learn the crafting menu, building, hunting, etc. without the danger of being killed by other players. Of course, you must still survive the environment and hide well when asleep.
When you log off your character will be asleep and as long as you aren't discovered/raided, then you simply continue. ****!!!!Make sure you know which server you joined in order to return to your character later!!!!!***** You can either write it down and search for the server or you can look at your server history in the game menu. I find the latter to be the easiest method. I have yet to have my character deleted due to a server restart as I have yet to experience a server restart. Resources simply seem to respawn and the structures go away after a predetermined time as already mentioned. There have been a few lag spikes here and there, but this happens everywhere and if you aren't savvy enough to pay attentiion to the ping level of the server you are about to join then there is no one else to blame but you.
There is in-game VOIP that is only heard by players within a rather healthy radius of your character as well as text chat, which is filled with noobs asking questiions they could easily get answered by visiting the Rust page on steam or wiki page found here: http://play-rust.wikia.com/wiki/Rust_Wiki
You can play Rust in fullscreen or windowed, the latter allowing you to page back and forth between the wiki help pages and the game. As always, you get out of gaming what you put into it. If you have a nice rig, then you will enjoy the graphics and have no trouble. Otherwise you will need to turn off the grass to gain FPS, etc.. All of the official, modded and community servers were packed yesterday with anywhere from 20-256 players and there are plenty of country-specific servers as well. I counted roughly 27,000+/- players on 800+/- servers.
I highly recommend this game and can only imagine what is to come. It is already very good at this early alpha stage and well worth the price. If its made by the creator of Garys Mod, then you know it will be interesting to see how it develops. I wrote this article in the hopes that it will help players decide whether to buy or not, as this is how I make my purchase decisions on steam. Viva the community and I hope I don't meet you butt-naked and starving in the wilderness as your being chased by a bear!