Assassin's Creed IV Black Flag

Unmissable - completes on finishing Sequence 11.

The final memory sequence - completing it beats the main story, so this is your story-complete unlock. Everything else (full sync, the open-world collectibles, the DLC) can be mopped up afterwards.

Recruit 500 crew members over the game - free captured sailors from ships you board and from convoys and cages. Board lots of ships and choose to recruit the survivors; it adds up across a full playthrough of naval combat.

Finish a multiplayer session with a loadout you've customised - tweak your ability set in the MP menu, then complete one match. Quick once you're in a working MP session.

Unmissable - completes as you finish the game's first memory sequence. Every memory replays from the DNA menu later, so nothing here is missable.

Unmissable story progression - pops on completing Sequence 2.

Board a ship without losing any crew members. Your crew joins the boarding melee, so complete the boarding objectives fast and protect your men. Do it on a weak schooner or gunboat where the fight's short, and upgrade your swivel gun and crew to help.

Unmissable - completes on finishing Sequence 3. Nothing to chase.

Unmissable - a forced present-day segment out of the Animus at Abstergo Entertainment. Completes as you play it.

Complete 25 Abstergo challenges - the present-day meta-challenges on your employee profile (do X in the Animus). They tick off as you play; you'll near 25 naturally, then top up from the challenge list.

Earn 50,000 reales total - the game's currency, from plunder, selling cargo, contracts and forts. Comes naturally; sell your looted goods at harbours and it stacks up fast.

Dig up a buried treasure using a treasure map. Loot a map (from a ship or chest), travel to the marked island, and dig at the indicated spot. Any one counts.

Unmissable story progression on completing Sequence 4.

Fully clear one location - all its viewpoints, chests, treasures, Animus fragments and activities. Pick a small settlement or island and 100% it; a locations map for that one spot makes it quick.

Unmissable - completes on finishing Sequence 5.

Swim a cumulative total of 1 nautical mile. You'll rack this up naturally swimming to shipwrecks, between ship and shore, and on dives. If it hasn't popped by the endgame, just swim laps off any beach.

Unmissable present-day story mission - unlocks as you play the forced Abstergo segment.

Unmissable story progression on completing Sequence 6.

Kill a guard as he rings an alarm bell. Let a guard spot you and run for a bell, then dart or chase-kill him mid-ring. Easiest to set up deliberately: break stealth near a bell and cut him down as he pulls it.

Plunder 30 ships - damage a vessel until you can board, clear its crew, and take the cargo. You'll pass 30 just playing the naval game.

Unmissable - completes on finishing Sequence 7.

Unmissable story progression on completing Sequence 8.

Unmissable - completes on finishing Sequence 9.

Complete a Templar Hunt sequence - the optional assassination side-quests where you hunt a Templar target across a few stages. Pick one up from the map and finish its full sequence; any one completed counts.

Unmissable present-day story mission, forced as the plot progresses.

Harpoon a killer whale (orca). Take the harpoon dinghy out to an orca hunting spot and spear it through the harpoon mini-game. Orcas only appear at specific open-sea markers, so a locations guide points you to one; keep the boat side-on and time your throws.

Unmissable story progression on completing Sequence 10.

Unmissable - the final present-day mission. Completes near the end of the game.

Unmissable story progression on completing Sequence 12.

Kill 4 enemies in a row with multi-pistols - the chained pistol kills. Unlock the four-pistol holster and the chain-kill skill, then in a group start a chain off a stealth or counter kill and tag four pistol kills in the one chain.

Capture all the naval forts in the Caribbean - batter each fort's defences from the Jackdaw, then board and kill its captain. There are a handful across the map; taking them also opens up the region and boosts income. All revisitable.

Share each type of discovery with a friend once - a Uplay/social feature, done from the map/menu's "share" option on each discovery category. It needs the online sharing service working; with Ubisoft's social servers flaky in 2026 this can be awkward, so try it when you're properly connected.

Fully upgrade your hideout at Great Inagua - buy every building and decor upgrade for your base. Funded by your income (forts, plunder, contracts); just pour reales in until everything's maxed.

Complete the Discovery (tutorial) mode of Wolfpack - the co-op MP mode. It's the short intro/practice run, so it's quick. Needs the MP servers up; do it when you're connected.

Unlock every tavern - each town's tavern becomes available once you visit (some need a quick scuffle or a nearby viewpoint synced first). Sail round the map and pop into each. They double as fast-travel and social points.

5 air assassinations from a swinging rope. Ships' decks and forts have hanging ropes - swing on one and assassinate an enemy below mid-swing. Boarding decks are full of them, so five come easily once you know the animation.

Complete every naval contract - the optional sea missions you pick up at taverns (sink a target, escort a ship, etc.). Work through the list; new ones appear at taverns as you progress. None are missable.

Explore all the underwater shipwrecks - the diving sites where you swim wrecks for treasure (you need the diving bell, unlocked in the story). Watch the sharks and manage your air; a locations guide covers every wreck site.

Unlock the secret door in Tulum - the vault opened by the Mayan Stelae. Solve the Mayan stone puzzles scattered across the map to collect the Stelae keys, then open the Tulum door. It rewards the Mayan armour.

Visit every location on the map - reveal every named spot (islands, towns, dive sites, forts). Buy the map upgrades from harbourmasters to surface the icons, then tour the whole Caribbean. Overlaps with the other completion sets.

Hack 15 computers in Abstergo Entertainment - during the present-day segments, use your hacking tool on the office computers you pass. There are plenty around the building; hack fifteen across the present-day sections (revisitable).

Wake up in a haystack after a night of drinking - a scripted Easter-egg tied to a specific tavern/drinking moment. It's a one-off gag with an exact trigger, so check a video for where to set off the black-out.

Craft the Hunter outfit - one of the craftable outfits made from animal hides. Check the crafting menu for its required pelts, hunt the land and sea animals that drop them (some need the harpooning of sharks/whales), then craft it.

Fully upgrade the Jackdaw - every hull, cannon, mortar, ram and swivel upgrade. Needs a lot of metal, wood, cloth and reales, gathered by plundering ships and selling cargo. Essential before Devil Of The Caribbean.

Defeat all 4 Legendary Ships - the toughest naval fights in the game. Fully upgrade the Jackdaw first (Destroyer): you want max hull, heavy shot, mortars and a strong ram. Each is a brutal duel - keep moving, punish with heavy-shot broadsides, and ram when you can. Take them one at a time. The hardest single-player achievement.

Free your first slave - at a plantation or from a slave ship. Do any one liberation activity. Your first step toward Seeds of independence.

The big MP grind: reach level 55 in multiplayer by earning XP across matches - hundreds of games' worth. Two problems in 2026: the playerbase is all but dead so matchmaking drags, and connections often drop into a "limited mode" that blocks MP progress entirely. Line up a boosting partner and pick a moment when the servers behave. Comfortably the hardest achievement to actually earn now.

100% of every main mission's optional constraints - the full-sync objectives (kill a certain way, don't take damage, finish under time, etc.) across all memory sequences. Replay any memory from the DNA menu to nail the ones you missed, so it's tedious rather than missable. The single biggest step toward 100%.

Kill 5 guards at once with a blunderbuss - the wide-spread pistol. Equip the blunderbuss, wait for five enemies to bunch tightly (a group charging you in a fort), and fire once into all five at close range.

Complete all missions of the Freedom Cry DLC - a standalone campaign starring Adéwalé in Saint-Domingue. Finishing its story pops this. Entirely separate from the main game; buy/launch it from the menu.

Liberate 500 slaves - free captives at plantations and from slave ships across the Caribbean. A steady grind; hit the liberation activities and slave convoys as you sail. Liberation Day is your first.

Play on every MP game mode and use every ability and ranged weapon at least once - a checklist across many matches. Work through each mode and cycle your whole loadout to tick off every ability and weapon. Slow and server-dependent given the tiny playerbase.

Kill an opponent using a lift you've trapped with the Booby Trap ability. Equip Booby Trap, rig a lift on a map that has one, and bait a pursuer onto it. Situational - pick a map with a lift and lure a target across it.

Playing as Blackbeard, land an acrobatic kill and a pistol kill within 10 seconds of each other. Pick Blackbeard, do an acrobatic (ledge/leap) kill then immediately a pistol kill inside the window. Its platform-twin Queen Anne’s Revenge wants a gun kill instead - same idea.

Playing as The Orchid, block 10 opponent abilities using Sabotage. Pick The Orchid, run Sabotage, and use it to block enemy abilities ten times over your matches.

100% synchronisation across Freedom Cry - every mission's optional full-sync constraints plus the DLC's liberation activities and collectibles. Replay missions from the Freedom Cry menu for any full-sync objectives you missed; nothing is permanently missable.

A story beat in Freedom Cry's finale - dispatch the Gouverneur as the DLC climaxes. Forced within Freedom Cry; just play through to the end. Comes alongside His Word Was “Perhaps”.

Play and complete a Game Lab session in the Multiplayer Public playlist. Game Lab is the custom-ruleset MP mode - queue it in the public playlist and finish one session. Needs enough players online, which is the catch now.

The platform-twin of From Queen Anne's Revenge - as Blackbeard, an acrobatic kill and a gun kill within 10 seconds. Same setup, a gun kill rather than a pistol kill; do the acrobatic kill then a fast gun kill.

Playing as The Jaguar, be the top-scoring player of a Domination match. Pick The Jaguar and play well enough to finish first on the scoreboard in Domination - far easier to arrange with a boosting group in a low-population match.

Rescue pirate hostages by using "dancers" to distract the guards. At a hostage-rescue spot with a dancer group, send the dancers in to pull the guards away, then free the captives while they're distracted rather than fighting through.