First it was Rockem Sockem Robots: Apocalypse Edition, then it was Neon Lights Building Sim, and now Fallout 4 has received an entire misty island's worth of DLC, with synths, religious fanatics, and angry fish thrown in. Far Harbor is impressive in size even with Bethesda's repeated insistence that it was really big; if you look for value in terms of pounds per square inch then Far Harbor is definitely the DLC you've been waiting for. But size, as we all know, isn't everything.
Fortunately Bethesda also know what to do with it. The change in aesthetic from 'Dry Urban Dilapidation Chic' to 'Irradiated Sea Fog Realness' is refreshing, and the island as a whole has a spooky atmosphere, with buildings and monsters looming suddenly out of the mist. If you're ever overwhelmed by enemies running away from them feels more desperate and panicked than on the mainland, because you really can't see where you're going, or whether what you're about to run into is a) a tree or b) a giant preying mantis.
Other new monsters are introduced, as well as high level versions of familiar ones, all along the same insectoid/marine life theme. Their design makes them good set dressing for the theme; it's plausible that a coastal area under a constant blanket of radioactive fog would eventually produce a giant angler fish–meets–frog monster that can spit fire. Even if it isn't plausible it's still enough to shit you up a bit the first time you meet one. Put all together the island seems alien compared to the mainland.
The strange, unknowable nature of the place is played up in the Far Harbor story. The main quest concerns the human residents of Far Harbor struggling for control of the island with the religious zealots of the Children of Atom, with Acadia, a colony of peaceful synths, caught in the middle. Almost immediately you're told that things aren't what they seem, and an overwhelming number of the plot points involve deception, shady motivations, and hidden identities.
DiMA, the prototype synth that you should definitely take Nick Valentine to meet, is the source of a lot of these, greeting you with the same tones as HAL 9000 told Dave he couldn't do that. But even if you are suspicious of him you're never sure if you should be. It's also an interesting chance to hang out with some of the Children of Atom without them trying to kill you and, as it turns out, they're pretty nice to their friends. Even the side quests, of which there are a good number dusted over the map as well as handed out by NPCs, are also about secrets and lies – a murder mystery involving robots is notable for not only this, but also for being fun and ridiculous – and as a whole the DLC balances shooty–fetch quests with potential social solutions more evenly than the main game did.
The honeymoon period never lasts forever, though. For some people it was over before it began because of performance issues on the PS4, and words like "unplayable" are being bandied around. In my 16 odd hours there were one – maybe two – specific bits of the map around Far Harbor itself where the frame rate plummeted. Some players are reporting worse issues, but my experience wasn't marred by it. It was decidedly playable. Your eyes will likely not go spontaneously blind rather than endure a single second more of the insulting framerate you are subjecting them to, rendering you incapable of completing Far Harbor. But it might get a patch or something anyway.
What can't be fixed is the worn out truism that familiarity breeds contempt, and although it starts off being all cool and creepy a soggy forest can only enchant you for so long, even if it has glowing fungi growing in it. In the latter part of the story you'll find yourself skipping back and forth between the same few locations, so by the end your familiarity is going at it like rabbits whilst the plot itself loses momentum. By the time the main thread reaches its conclusion you'll probably have been ready for it for at least an hour.
Far Harbor is a DLC that winds down rather than winds up, but it gets away with it. It uses a design that's refreshing even if it does eventually sour, and packs a lot of fun into all the quests you can pick up. Out of all the DLC Far Harbour gives you the most bang for your buck, and it's timed well enough that you were just getting ready to go back to the game anyway. Plus it's a chance to relive those happy family memories of rockpooling on your summer holidays. Just with more horrific mutations. Plus there's an incidental story you can stumble on that references WWE, which I didn't fully understand but am told is very good.