If you simply ran out of things to do in vanilla Destiny 2, its first DLC expansion, Curse of Osiris, adds a few new activities for you to take on. It introduces a new setting in Mercury, a short campaign, new weapons and gear, Strikes, Crucible maps, Adventures, among smaller things. But aside from the brief but fun Raid Lair, the new stuff in Curse of Osiris doesn't add anything substantial or interesting to Destiny 2 to make it worth revisiting.
Curse of Osiris picks up right after the end of the base game's campaign, as far as your level goes. You could go directly from the end of the Red War story to Curse of Osiris' campaign, which requires a power level of 200 to 220, without having to grind much in between. For newcomers or PC players who've had less time with the game, it's a comfortable bridge for leveling up between the lower-level vanilla content and the high-level endgame activities like the Nightfall. (Those endgame activities are a different story, but we'll get to that in a bit.)
As a result, though, Curse of Osiris' story missions feel like filler. The campaign sets up an enormous undertaking against the Vex, with infinite timelines and computer simulations and the mysterious Warlock Osiris mixed up in it all. But with a two-or-so-hour runtime, the missions rush through the interesting concepts and usher you into a simple final battle that is essentially scripted. It's not enough time to fully understand Osiris as a character, which is disappointing considering he's only ever been mentioned in Destiny lore before now.
The beautiful and varied Infinite Forest, a Vex creation designed to simulate timelines and their infinite permutations, is the most interesting addition in the expansion. Within the Forest, you can travel to a simulation of the past, a much more vibrant and lush version of Mercury that's stunning to look at. But even then, the story doesn't task you with exploring it or any other location in the Forest, instead shepherding you through areas to find codes and things that smarter NPCs can use to pinpoint your next destination for you. The lack of callbacks to Vault of Glass from Destiny 1, another time-bending Vex creation, is also a letdown.
Other than the Infinite Forest, the new destination, Mercury, is simply uninteresting to explore. It's a small circular map with one new Public Event, a new vendor, and a handful of chests and Lost Sectors. The foundation of exploration established in the base game is still good here--having a variety of options to choose from does make things feel less repetitive--but it feels like busywork with little to do at the highest level. That extends to the new Strikes, which are almost direct copies of two of the story missions, nothing more than another way to kill time.
The biggest problem with Curse of Osiris is that it locks certain high-level activities, including the Prestige Nightfall, behind its new power level cap. The recommended power for the Prestige Nightfall in particular is 330, which you can't reach if you don't have the Curse of Osiris DLC. So if you don't get the DLC, you suddenly don't have access to something you used to be able to do. It's also frustrating if you do get Curse of Osiris, because the higher level requirement doesn't fundamentally change these activities.
New Heroic Adventures add Nightfall-style modifiers to the Adventures on Mercury, but those missions aren't begging to be replayed. The main incentive to do them at all is to unlock a Lost Prophecy quest from the NPC Brother Vance, which is one of most tedious fetch quests in all of Destiny 2. If you do manage to gather 10 of the necessary item (through repeating Public Events and finding chests), you unlock the Forge, where you can craft Legendary Vex weapons. But for anyone besides the most dedicated players, there's no compelling reason to do all this unless you want to redo old missions on harder difficulties in order to get loot to use when you do them again.
While some of the new loot is worth collecting--my favorites so far include the Legendary automatic scout rifle Metronome-52 and the broken but ridiculously fun Prometheus Lens Exotic--you'll likely get a lot of duplicates before you get anything you actually want to use. Because the main reward for everything you do is shiny new loot, the frustratingly high drop rate of duplicates makes grinding more disappointing than satisfying. The gunplay feels as great as ever, though, so it can be fun to experiment with new weapons, but it's not enough to sustain an expansion that adds little outside of extra busywork.
The excellent gunplay is not enough to sustain an expansion that adds little outside extra busywork.
The Raid Lair, while shorter than a typical Destiny Raid, is the one late-game addition that's worth trying. Eater of Worlds is set on Leviathan, the setting of Destiny 2's first Raid, but with a different boss and separate areas to explore. It features a mix of Destiny-style puzzles, including a platforming sequence and fun with orbs, but in a less time-consuming package that's a welcome alternative to the full Leviathan Raid. Using careful teamwork to solve puzzles is rewarding in ways that the story and simple Strikes aren't, and combining that with the right loadout and strong shooting skills shows what Destiny can be when it leaves the filler behind and makes the most out of its best mechanics.
But in almost every respect, Curse of Osiris doesn't elevate Destiny 2 beyond what it was at launch. Especially for lapsed players, the same old activities reskinned for an unremarkable new setting make them feel more like chores than ever, and the interesting ideas in the Infinite Forest aren't at all used to their potential. There's still some fun to be had in finding new weapons and maybe tackling the Raid Lair, but reaching that point is so tedious that it hardly feels worth doing.
Editor's note: When we first published our Curse of Osiris review, both the Prestige Nightfall and the Prestige Raid were set at the 330 power requirement. In a recent post, Bungie revealed plans for a hotfix that will reduce the Prestige Raid requirement to 300, making it accessible to all players. The Prestige Nightfall will remain at 330. The review text has been updated to reflect this change.