These parts feel much more like a classic adventure game rather than an FPS, and are actually rather clever, enjoyable and can give the game a unique atmosphere.
So it's a shame that there isn't more of this atmospheric action, as no sooner do you settle into the adventure side of things, than you will be forced into a gun-toting body for another slice of woefully inadequate shooting action.
In fact, it's virtually impossible to catalogue all of Geist's failings where the FPS action is concerned, simply because there are so many. However, there are specific, niggling things about the shooting that are simply inexcusable.
Firstly, the weapons feel completely insubstantial. The fact they all have infinite ammo isn't really a problem, seeing as battles hardly ever transcend more than a handful of rooms, but the fact they feel so light, so weak and so pitiful is very disappointing.
Even your final weapon is incredibly puny - and forces you to use its secondary grenade function (accompanied by a truly awful 'peew' sound) if you want to make any headway.
Also, the problems with the controls are really highlighted when fighting. For example, headshots aren't as simple as they should be because you're fighting the less-than-subtle controls, which makes fine tuning your aim a case of luck over judgement and turning on the spot sluggish and unwieldy.
Thankfully though, the difficulty level (or rather, lack of) is such that it's excusable to a point which, unfortunately, is something that can't be said for other aspects of the game.
The final nail in Geist's ghostly coffin is its almost astounding patchiness. Throughout the course of the game, you're witness to a myriad of different ideas. There are so many disparate concepts, and unfortunately they never really gel.
The result is a mess, and although these concepts work in theory, it feels like they've been put into the game with little regard as to how they're supposed to fit together, let alone how they make the player feel.
The environments, for example, differ so wildly you never really understand what the hell is going on. One minute you're fighting through a train, the next there's a distinct sci-fi feel, and after that you're in what looks like ancient Greece, fighting giant stone statues with laser-eyes.
The result is a mess of a game that never really flows properly, with a pacing that's all out of whack. You'll be flying through the game at one point, the next you're wandering around aimlessly, looking for something - anything - you can interact with in order to progress.
In one case, we spent 45 minutes looking for a can of soup we didn't even know we needed until, purely by chance, we saw our cursor highlight it in passing.
It's not just the vagueness of your objectives that's disappointing, either. There are a number of small details that seem tacked on for no reason.
There's a stupid little rhythm game that crops up for a couple of minutes. Or there's the truly irritating Simon-says-style game where you have to hammer rivets (yes, rivets) into panels. With all that's gone before, these games seem completely out of place.
If ever there was a case for the importance of taking a single core idea and exploring it fully (even if it means a shorter game), then this is it.
Second Sight, for example, did it perfectly - Free Radical built the game around its core ideas of extra sensory perception, possession and telekinesis and wrapped it up in a superb plot.
Geist simply has a handful of ideas, some of which are brilliantly executed, some of which aren't, and they've simply been slapped on top of a very average shooter.
It wouldn't be quite so bad if, after all these disappointments, there was an engaging storyline to keep your interest, but there isn't.
Initially, it's intriguing - particularly when it comes to learning who Gigi is, how she came to be and the exact goings on in the mysterious corporation you're investigating - but the more the game disappoints, the less you find yourself caring.
By the time you get to the final boss encounter, you won't care for the characters, you'll grow frustrated by the clumsy, disjointed way the tale is told, and ultimately you'll just want it to end.
Which is sad, because it means that many of you will never get to see those brief moments of brilliance that are hidden in the game, but we simply can't come up with a good enough reason for you to go looking for them.
The truth of the matter is that it looks like N-Space, the developers behind such classics as Mary-Kate and Ashley: Magical Mystery Mall and (our particular favourite) Rugrats: Search for Reptar, in this case couldn't transfer their skills from toddlers and shopping to ghosts and guns.
Geist will be released for Gamecube on 15 October