Fallout 4 is that game. Set in Boston, Massachusetts after the world has been ravaged in a nuclear apocalypse, Fallout 4 puts you in the body of a survivor of a "Vault", a place where people fled when the bombs fell. Of course, the vaults weren't just bunkers, but I'll leave that for you to discover.
As you wander the wastes, you encounter allies, enemies, monsters, settlements, and ruins a-plenty. There weapons from handguns, to miniguns, to plasma and laser cannons. (And an actual cannon!). There's robots, androids (synths), and suits of power armor aplenty.
Fallout 4 is a role-playing game, in that you choose your armor, weapons, and you decide whether to hurt people or help them. When you come across a new settlement, you can help them rebuild and craft defenses, food and water stores, buildings, call more decent people to the settlement. Or you can murder them all and be on your merry way after looting everything they own. This even pertains to conversations you have with people. You typically get four choices of replies, ranging from kind, to blunt and cruel. Just be aware that while there is no specific endings for being good or being evil, your choices do have repercussions.
Finally, while there is a fairly intriguing main storyline to follow, it's not time based, and you can honestly spend HOURS just building settlements, exploring ruins, and doing side missions.
The controls are pretty standard, and you can switch back and forth between First and Third person point of view, which helps the game appeal to those who like a more traditional RPG, or those who like FPS more. The graphics are fairly standard for the current generation of consoles and PC as well, with backgrounds that stretch off into the distance and detail abounding in the environments, equipment and characters.
Of course, no game is flawless. Fallout 4 suffers mainly from the same problem as many other large, open-world games. There's just too much. Too many textures, too many options, too many chances for things to cross unfavorably and create glitches. This is just something we have to live with as games get more and more complex. Textures bind up and don't load, figured get trapped in loops or in places they're not supposed to be. It's not even uncommon to get caught between two textures like land and water, and end up falling out of the world. (How's that for surreal?)
My biggest personal issue with the game was its auto-save feature. The fact that it's there lets you get complacent with making manual saves, however when shit goes down, (and it will) the effort of going back and forth trying to figure out what went wrong means you're likely to trigger the auto-saves before realize you need to go back to a previous save, and when you go to use it, all of them will be after the point that you need to go back to. I lost multiple hours of progress SEVERAL times due to this. I was not a happy camper.
Still, this game will keep you occupied for weeks or months if you let it, and with DLC coming out in the coming months, dedicated players may want to put extra padding on their couch. You won't be getting up for a while. Definitely worth getting for fans of RPG's, Dystopian futures, and story-centric FPS players.