Keep It Simple, Stupid:
A concise analysis of Fallout: New Vegas
Fallout New Vegas should be the norm for games. It is not. It is the apex.
That's a rough statement to make. FO:NV is by no means perfect - it's hitched to the absolutely horrendous engine of Fallout 3, and there's certainly some holes and weaknesses in its writing. Personally, I could've done with a less clear split between the NCR and the Legion from a moral choice standpoint. But let me say first what Fallout New Vegas does extremely well that many games skimp on or even don't bother with.
Fallout New Vegas creates a detailed setting. Fallout New Vegas creates a plausible scenario. Fallout New Vegas allows the player to interact with the setting and scenario.
Three little things. Three little things that make all the difference.
Games are an interactive medium. It is their nature. It is why they are "games" and not "movies". Games tend to forget this, perhaps because it's harder to make a game interactive, or perhaps because they desire to emulate movies and gain some measure of their respectability. But games are games. Games are interactive. Games have a player, and the player does things. Do the things matter? It depends.
In Fallout New Vegas, the answer is "yes". In very simple ways, too, not big complex ones. Hell, I could probably make something akin to New Vegas just using the Neverwinter Nights module designer. There's factions whose opinion of you is influenced by your actions. There's quests. There's multiple story paths. The world is "functional" and "open", rather than being a super-scripted set of corridors. It's not super-unique programming, it's just normal design for an RPG.
But it's also one of the only games that's bothered to do it.
I can name maybe a few others off the top of my head. "Mercenaries" and "Way of the Samurai" are the main ones that spring to mind. Games where the traditional mission-based open-world setup is broken up by the possibility of having different allegiances and causing different things to happen. The possibility of gameplay having an effect on the way those allegiances turn. The idea of a game being actually interactive. The work put in to make the world feel "real" and "tangible" rather than being a playground or "video game level". Little things. Little things that make the player feel like they're doing something and not just being carted along a theme park ride.
Compare FO3 to FO:NV and you'll see that apart from the totally questionable handling of the setting and tone, the biggest difference is that FO3 is a single story with minor variations, and FO:NV is about a culminating event where the protagonist can be on one of many different sides. And that's it, really. FO:NV gives you a scenario and lets you approach it. FO3 drags you by the hand to a console with three buttons on it and demands you press one. It's almost grudging about it, too, like it wouldn't bother but it feels obligated to do it. And I'm not sure that's the kind of thing we should accept in an interactive medium, especially from a game that brands itself as a "roleplaying" game.
Frankly, that's all I have to say about that.