Pros:
-Love the new and reimagined areas - the game feels truly revitalized and reminiscient of the world of Roadside Picnic.

-Despite earlier complaints about too much to explore, the bigger maps can be very fun to walk around in and appreciate the desolate scenery. I loved the Forest - driving around in a beaten up car, carefully negotiating an anomaly-covered road while passing swamps full of shambling abominations and bandit holdouts is what a game like STALKER should always aspire to be in terms of atmosphere and lonewolf gameplay.

-Shooting is fairly solid, albeit largely unchanged from original SoC.

-The "belt" function is an interesting feature that requires one to think ahead before plunging into an encounter.

-New mutants are implemented in a very interesting fashion that fits in with the world. The aforementioned swamp monsters are a stroke of genius; not to mention the leprechauns. Many of these new mutants are used sparingly, and some only show up once. Every time you stumble upon one of these things it's like you're discovering a new, forgotten species - and they often don't -want- to be found. I cannot begin to describe how perfect this is in terms of atmosphere.

-Artifact transmutation is actually pretty fun and rewarding, although the scarcity of rare artifacts to use in the recipes kinda hamstrings this a bit.

-New and unique artifacts reinforce the baffling nature of the Zone - many of these can only be found on dead bodies or in stashes.

-You are often forced to work with factions that would normally be enemies (IE: red,) which makes for some interesting situations.

-Some legitimately fun scenarios, such as the security system pursuing you through one of the labs, and a chase sequence involving a helicopter. There are also many enjoyable missions - unfortunately I never pursued faction membership with Duty, so I probably missed out a bit!

-Sidorovich and Strelok have good voice acting - some of the writing is pretty good, and the core characters are well drawn.

-Gloriously homoerotic ending with Ghost. Sure man, let's go to Alaska together.

-More STALKER! For better or worse, it takes an familiar system and pumps it up to eleven. It's wonderful to return to old areas and see how they've changed, or to visit completely new ones and see what's out there to discover.

Cons:
-7 year development cycle doesn't seem to have removed some very obvious bugs from the released result, nor deliver on all promised features. This is a game that basically demands fan patching.

-Enemy AI is laughably bad, but this is thankfully an easy fix for fan patching.

-While the game itself is remarkably stable, utilizing almost any of the new features leads inevitably to a futile struggle with CTDs. (repair menu, contacts list, car trunk, etc.) It makes one wonder why they were included at all if they barely work.

-Far too many worthless areas to explore, filled with cleverly hidden loot caches that contain absolutely nothing. This is more of a pro/con point.

-Some artifacts are ridiculously difficult to find cause of their lack of glow (you can only find "thorn" style artifacts when you bump into them.) This is especially bad when you're in a wide open space.

-Plot is bizarre, confusing, and ultimately pretty dumb. ("Gordon Strieman" Half-Life pastiche sequence and basically every time a flashback happens) SoC is barely any better, but it makes up in terms of mystery and restraint. LA reveals almost too much, and the end result is underwhelming and - it bears reiterating - horribly confusing. For STALKER, less explanation is immeasurably more important to the atmosphere and ethos that Roadside Picnic started than mountains of clumsy exposition.

-There are many events in the game that suffer from lousy, unclear writing - what's happening, why, to what end, etc. Many plot elements go absolutely nowhere and this becomes especially clear every time you enter a lab for whatever vague purpose the plot requires of you. The worst offender in this category is the weird, hooded agent who pursues you across the game, only for absolutely nothing to come of this. The identity of his controllers are likewise never explored beyond a single cutscene... though to be honest, this is probably for the best, as I'm sure the answer would be stupid.

-While we're on the subject of labs, I never thought I'd say this but... there's way too many of these things. STALKER excels in a desolate, open world format. The occasional jaunt underground is often fun, but Lost Alpha abuses this concept.

-In-game cutscenes, with their reliance on the same bad voice actors and janky character models, are like a shotgun blast to the face for atmosphere. It doesn't help that they're often flashbacks that reveal absolutely nothing interesting.

-Poorly implemented upgrade system. It's often unclear what some upgrades actually do, and being locked into a single upgrade path feels cheap and arbitrary.

-There's little sense of resource scarcity - the Zone is practically brimming with food, water, and ammunition. Money, likewise, is trivially easy to get.

-Endgame "boss" is utterly pathetic, explains nothing, and basically only exists to give you yet another poltergeist to fight at the end.

-... It's basically just more STALKER. The extended plot ultimately feels like an unsatisfying addition to an already complete narrative.