Firewatch is a game about rambling. You'll spend much of Campo Santo's outdoorsy adventure navigating the Wyoming wilderness on your lonesome, chatting with a lady who you've never met over your handheld radio. Forget the walking simulator – this is very much a walkie-talkie simulator. But if you go down to the woods today, can you be sure of a surprise? Well, yes – but not entirely of the pleasant kind.

The first-person foray puts you in control of Henry, a bearded ranger who's taken a job in the American outback to escape his everyday life. It's here that the wedded wanderer strikes up a relationship with Delilah, the sharp-witted supervisor at the Shoshone National Forest. A large chunk of the four hour story centres upon the dialogue between the duo, as you use the DualShock 4's triggers to fire topics of conversation at your accomplice – a welcome change of pace from the almost obligatory bullets.

Perhaps more powerful, though, is the sea-change to the story-driven genre that this represents: D, as she's affectionately nicknamed later in the game, is only ever represented by voice, so the title leaves you to build up your own personal image of her. And, as with real-life, the things that you say will have an outcome on the way in which conversations play out: ignore her questions and she'll remember your evasiveness; act inappropriately and she'll temporarily step away from her radio – leaving you on your own.

The game's at its absolute best in these moments when you're alone, as the interesting debut really does capture the sense of solitude that real-life rangers must feel. Being set in the late eighties, there are no smartphones or computers to keep you connected – aside from Delilah, you're left entirely isolated. And the game uses this seclusion to its advantage: you must manually navigate your way through the moderately-sized open world using a map and compass – it's lonely out there.

Fortunately, the forest views are magnificent. Olly Moss, the massively influential English artist, contributed to the title's look, which uses striking primary colours and cel-shading to create a simplistic yet vibrant style. The many summer sunsets scattered throughout the story are arguably the most impressive, where burning oranges contrast the deeper purples of the encroaching night skies. The release uses many different lighting techniques to convey the various times of day, and this helps to contextualise the passing of time as you hike from destination to destination.

The problem is that the game, in its pre-release state at least, has some of the worst performance issues that we've seen on the PlayStation 4 to date. The framerate chugs like a teenager at a house party, stuttering to auto-save and plunging into the low teens as it streams in new environmental data. Granted, this is not a title that ever requires flawless controller response, but the constant juddering is still jarring regardless.

Perhaps the bigger issue, though, is that the story stumbles like a rambler without a walking pole. It opens excellently with some pretty heavy exposition, but the wise-cracking nature of the cast makes it hard to empathise with the protagonist's plight. The early themes eventually grow back to the fore, but by the time that the title's ready to tackle them head-on, it's difficult to believe anything that the character has to say. Everyone deals with grief differently, of course – but Henry does not behave in a manner befitting of a man who's just been dragged backwards through the emotional wringer.

To be fair, this isn't the fault of the voice acting, which is exceptional throughout – it's the overly witty nature of the writing that's the problem. The game does proceed to build a mystery in parallel to the main plot thread, but despite its best efforts, this brief blast of paranoia ends abruptly and expects you to care deeply about a cast member that you barely even know.

And with the story being the sole reason to ready your rucksack in the first place, you'll feel bitterly disappointed by the time that the credits roll. After all, the gameplay – of what little is here – consists of constantly backtracking through environments that you've been to before, and while the title does switch things up ever so slightly by changing the look of your surroundings, you'll have had your fill of hiking long before the end of the adventure.

But, of course, the developer would argue that the destination isn't important here: it's all about the journey, and the attachment to a character that you've never met. But while this is an undeniably refreshing release, it never really measures up to its one bright idea; the odd engaging exchange aside, the game doesn't really go anywhere. Sure, there may be something figurative lurking inside its very human conclusion, but we can't shake the feeling that we'd be giving the title too much credit if we started scavenging for metaphors.