Welcome back to the wasteland. Sure, some things have changed on the surface, but there’s no mistaking that you’ve returned to the post-apocalyptic world of “Fallout.”

“Fallout: New Vegas” — an M-rated role-playing game developed by Obsidian Entertainment for Bethesda Softworks — is a direct successor to “Fallout 3,” the 2008 game that took players to a nuke-ravaged Washington, D.C. Almost everything that made that game so popular returns with only a few modifications.

You play as a messenger who’s gunned down in the opening scene. After being revived, you spend the next few missions seeking your missing package — a computer chip — and your revenge. It is then your task to prepare for a looming battle over the Hoover Dam, which supplies power to New Vegas and to the expanding New California Republic. This requires running errands, engaging in diplomacy and eliminating threats for a number of factions that will fight or provide support in the battle.

Once again, the game offers an excellent mix of exploration, quests and fighting. The storyline is rich and complex. And, of course, your actions and decisions will have an impact on everything from the way people react to your presence to the way the story unfolds. For example, helping a gang of Elvis impersonators will raise their opinion of you. However, it’s very likely that you will alienate other factions in the process. And that’s important because the friends you make during the game are likely to affect the game’s ultimate outcome. In addition, certain actions will determine whether you’re seen as a saint or a sinner — a matter that weighs heavily in certain interactions.

The wide-open world of “New Vegas” is populated by an interesting collection of characters. Followers of a wannabe Caesar, paladins of the Brotherhood of Steel, warlords and vagabonds add intrigue and color to the wind-blasted gullies, moldering ruins, underground bunkers and remote settlements that dot the landscape. Amid it all live the gangsters, gamblers, soldiers and hookers of New Vegas — a bright and glitzy survivor amid the desolation. And almost all of them have interesting missions and side quests to offer.

Since Las Vegas was one of the few cities to be spared nuclear destruction, a few game play elements differ from those in “Fallout 3.” For example, there’s a reasonable amount of vegetation, considering the area started off as desert. And you can drink from an abandoned toilet without having to worry about receiving a dose of radiation. However, you’ll still find a good number of two-headed cattle, fierce super mutant warriors and desiccated ghouls.

Among the other changes are new gadgets and weapons, new perks available when leveling up, a new system for granting temporary bonuses to certain skills, a new interface for dealing with companions, several methods of gambling and new options for creating ammo, weapons and aid items.

However, the basic look and feel of the game have actually changed surprisingly little — and that’s not always a good thing. While the settings, objects and characters are well rendered, the animations are very wooden. It’s still common to see characters floating in the air or see the frame rate stutter as you’re running across the countryside. And, the game freezes all too often.

Hookers, drugs, alcohol, profanity and exploding heads are back, too. In fact, almost all of these family-unfriendly traits seem a bit more prominent than in “Fallout 3” — you are in “sin city” after all.

A “quick” play-through of the core missions and a handful of side quests was all I could accomplish before writing this review. Despite a few concerns, I definitely fell for “Fallout: New Vegas.”

Platform: Xbox 360 (tested), PlayStation 3, PC

Online: http://fallout.bethsoft.com