The Division has undergone several transformations since it first launched back in March, but the core shoot-and-loot setup has remained an exhausting time sink that’s both aggravating and exhilarating. Whether you’re still smitten with its grindy gear hunting or surrendered to its bullet sponge enemies months ago, the game’s first paid expansion–Underground–offers an enticing package that includes new gear sets, a third Incursion, and an entirely new way to engage the game: Underground Operations.

According to the simple yet sound story framing, the forces you fought during the campaign have since regrouped in New York’s labyrinthine subway system, and it’s up to you to flush them out. The resulting missions play like a strictly cooperative PvE version of the more PvP-focused Dark Zone, though Underground’s operations function more like a new mode than a new area. Operations take place away from the open-world setting in randomized “dungeons,” allowing for discrete, repeatable missions with adjustable difficulty and gameplay variables.

Despite being randomized, levels end up looking just as detailed as the desolate city above, with creepy lighting and believable destruction throughout. Areas seem to fit together naturally, too; though I encountered a few strange bottlenecks and began to recognize certain reused sections after several hours, I was consistently impressed with the variety of the level layouts. And although Underground’s tunnels are populated with the same enemies you fought topside, they’ve developed some new tricks that noticeably impact the flow of combat, namely alarms, environmental traps, and jammers that disable your special abilities.

For even greater variety, you can apply any combination of Underground’s five “Directives” to any mission. Each one handicaps your team in some way–from disabling the mini-map and directional damage indicators to steadily draining your health as you play–but all of them grant you bonus loot and XP if you’re successful. It’s a clever way to add an enjoyable, optional challenge and extend Underground’s longevity. Unfortunately, Underground forces you to unlock new Directives one at a time over the course of many, many hours. Given that you can only tackle these missions if you’re already a veteran player, this arbitrary gating feels like pure padding.

The one upside to the padding: Underground’s operations are probably the most reliable source of quality loot in the entire game. Every mission ends with a boss and a loot chest, both of which tend to yield high-end weapons or better, and every time you level up, you’re gifted a cache containing a random item. Anyone who’s spent days grinding through dailies in order to earn a high-end gun knows exactly how exciting this is, especially since Underground also adds four new armor sets.

The four horsemen of the Dragon’s Nest Incursion. Bring a health station.

For the uninitiated, equipping two or more items from the same set unlocks special stat bonuses. In this case, those bonuses boost particular playstyles, subtly but smartly encouraging you to carve out a specific role. One set aids support players by improving the effectiveness of the health station, for example, while another helps damage-dealers by reducing reload times. Each set offers something unique that’s worth working towards, which–combined with the addition of weapons and items with a 240 gear score–makes The Division’s loot meta-game alluring again. The one annoying drawback to Underground’s generous reward system: desirable vendor items still require Phoenix Credits. Even though I had a stash full of high-end weapons, I didn’t have enough Phoenix Credits to buy items or blueprints since there’s still no way to sell gear for anything besides basic currency.

If all this talk of gear scores and Phoenix Credits has you confused, don’t worry: Underground actually provides a reasonable re-entry point for lapsed players. You’ll be miserable the first couple hours as you try to figure out how the game’s changed, but if you overcome this opening hurdle, Underground’s gear rewards will catch you up quickly. Solo players be warned, though: every Underground mission is a “no respawn zone.” If you die without anyone around to revive you, you’ll be booted back to base. Honestly, it’s not worth playing alone.

Beyond its random dungeons and added gear sets, Underground’s other major addition is The Division’s third Incursion, Dragon’s Nest–which, despite some cheap, fiery nonsense, is the strongest of the three. This time around, the usual grenade spam is also accompanied by stealthy, speedy RC cars that explode into flames and, if you’re under 200 gear score, will probably down you in one shot. You also have to deal with four simultaneous bosses who emerge from all four corners of a rooftop arena, all while snipers and shotgunners consistently drive you out of cover–pretty frustrating considering The Division’s health and damage systems rely on players being able to remain in cover and move tactically between obstacles. I had more than one team give up and disband, which forced me to replay the early portions of the mission with a new squad.

In a perverse way, however, the extreme challenge is a good thing. It forces your squad to work together and potentially makes all your loot hunting pay off. I had a respectable 188 gear score when I first attempted the Incursion, but still got repeatedly massacred, as did my teammates. When I tried again later after raising my score to 205–completing a new gear set in the process–I finally managed to dodge enough deadly RC cars to rip through those four bosses. Plus, the final room–which requires you to flip switches while avoiding entire sections of the floor as they burst into flames–is more thoughtful, creative, and distinct than anything we’ve seen from an Incursion before. It might be a pain, but Dragon’s Nest is definitely a step in the right direction.

And though not technically part of the paid expansion, it’s worth noting The Division’s sweeping 1.3 update launched right alongside Underground, adding new weapons, one additional gear set, a special Dark Zone bracket just for players for a gear score of 231 or higher, a Heroic difficulty option for two existing missions, the ability to recalibrate weapon talents, and more. Overall, the 1.3 update so far seems to be a resounding success, balancing out some of the odd changes implemented in the 1.2 update without introducing any major new bugs. So whether you purchase Underground or not, you’ll find a Division that’s arguably more polished and balanced than ever.

But those who do pick up Underground will also find a new way to play. The core mechanics and bullet sponge enemies haven’t changed, but the option to engage in short bursts of customizable, cooperative gameplay provides a hugely welcome alternative to simply replaying story missions or struggling through the Dark Zone. The unnecessary leveling system might slow the fun and solo players may suffer, but even Agents diving back in after months away can now enjoy new gameplay variations and the pick-up-and-play nature of Underground’s 15- to 20-minute operations. Assuming they haven’t burned out entirely, that is.