Over the past few months developer Bethesda has been continually rolling out downloadable add-ons for its post-apocalyptic epic Fallout 4. Every time I think I’m done, a new location or character or box of toys appears, and I’m pulled back into the nearly year-old game. Whether it’s to build a killer robot or design an underground bunker or explore the massive and mysterious island of Far Harbor, each of these further forays into Fallout 4 has managed to build on the base game with great new features and story elements.

Last week, Bethesda released “Nuka World,” the final expansion for the game. Set in a sprawling amusement park, it has all of the hallmarks of a great Fallout adventure — fantastic setting, interesting characters, lots of new lore — but unfortunately betrays all the creativity by forcing you to spend hours mindlessly shooting robots.

Nuka World is sort of like Disney World, only if you replaced Mickey Mouse with a bottle of Coke. It’s a glorious, huge shrine to Nuka Cola, the beverage so iconic its bottle caps have become the de facto currency in Fallout’s radiated wasteland. Much like Far Harbor, Nuka World is an area separate from the main map of the Commonwealth, Fallout 4’s take on a post-apocalyptic Boston. To get there you’ll need to take a surprisingly still-functioning monorail.

From the earliest moments, “Nuka World” thrusts violence upon you. The monorail station is deserted when you arrive, save for a voice over an intercom announcing that you’re about to enter the “gauntlet.” The gauntlet is a deadly maze, filled with turrets, poisonous traps, flamethrowers, and all manner of deadly obstacles. It took me three tries to make it through alive. (Its maze-like structure also proves difficult for Fallout 4’s companions; my robot buddy Ada kept getting stuck on walls and crumbling staircases.) The trial ends with a long, repetitive boss fight in a bumper car arena.

Once you’re able to enter Nuka World proper, it feels like nowhere else in Fallout. A malfunctioning robotic bottle of cola greets you at the entrance, and the main square is home to a large market, an arcade, multiple restaurants, and the headquarters of three different raider gangs. Very early on you’re put in charge of the whole park — I’ve lost track of just how many settlements and groups I’m the boss of in Fallout 4 — which means dealing with all three sides, and trying to broker a kind of peace. It’s the typical Fallout dilemma, presenting you with multiple factions, all with opposing viewpoints, and then forcing you to essentially pick a side. (This time, though, you at least get a sweet office space, with a bird’s-eye view of much of Nuka World.)

The raider gangs are one of the best parts of the expansion. The Pack, in particular, are just a fantastic addition to Fallout lore, one that shows a completely new side of the raiders. They’re a group of wild raiders that base their social structure on the animal kingdom. Their headquarters is full of animal cages, guarded by fighters dressed as colorful elephants and zebras. Their leader wears a necklace of animal bones and a neon pink-and-green striped mohawk. The Pack are joined by the bloodthirsty Disciples and the money-hungry Operators. All three live together in Nuka World under an uneasy truce, but when you arrive it’s immediately clear the peace won’t last much longer. Navigating this perilous situation is the crux of “Nuka World.”

Unfortunately, how you go about doing so is uninspired. While the main square of the park has essentially been transformed into a large, safe trading port, the rest of Nuka World remains unusable. All of the attractions, from the sci-fi district to the children’s zone, are filled with dangers. Your goal is to clear them out, and then assign the districts to the different raider gangs. The latter objective is fascinating, and requires some difficult decision making. The former, meanwhile, boils down to shooting a seemingly unending supply of robots, ghouls, and mutated wildlife. Clearing out the various districts is a long, tedious process that will test both your patience and your ammo supplies.

What makes this drab mission structure so disappointing is that Nuka World is such a superb piece of worldbuilding. Wandering around, you can discover so many fascinating little details about Fallout’s world. Everything from how the influx of robotics impacted the park and its staff (yes, there were a few disturbing psychological experiments going on) to the sheer scale of the Nuka Cola corporation. I’ve spent much of my time collecting the many cola variants around the park — including the alcoholic Nuka Dark — and using them to decorate my new office. As you explore the park you’ll be able to wander through a robot battle theater, and hop on a ride that takes you through what the future of vaults could one day look like. Even as a Fallout veteran, I kept learning new things about its backstory.

The richly detailed location is the main reason to play through “Nuka World.” There are some other benefits, like the plethora of new robot parts you can pick up from the military-grade security force, but really if you choose to grind through the monotonous campaign, your main reward will be a more complete understanding of this intriguing post-apocalyptic universe. Unfortunately, outside of lore and a handful of items, “Nuka World” doesn’t add much to the Fallout 4 experience — in fact, after the bevy of unique and creative expansions that came before, it feels somewhat regressive.

Much as the Nuka World theme park itself is designed for hardcore fans of a sugary beverage, Fallout 4’s final expansion is really only for the dedicated.