STALKER was one of those games that were plagued from the get-go by a bunch of technical problems, crashes, bugs, glitches and even poor gameplay choices at implementation. A few patches down the line and most of those problems vanished into the ether and were never spoken of again. The problem is, we get games for review 'as they are' and it's very rare we'll get a day zero patch that fixes the problems we've encountered. Then there's the whole rigmarole and box of active grenades that comes from daring to review something that's been patched, because, there are people out there who don't have an active internet connection and can't get the patch.

STALKER: Clear Sky, the official prequel to the events from STALKER follows in the STALKER tradition, laden with issues from the start and a few departures that endeared STALKER to its many fans. It isn't a bad game, it isn't a good game, and it's pretty much an average game that will probably become much better when the community or the developers fix the technical difficulties and crashes that happen all too often.

There are bugged mission triggers; these are almost the staple of the RPG-like FPS that is STALKER. Sometimes they work but more often than not they don't, leaving you in the middle of the Zone looking around and waiting for an attack to come for hours, an attack that never arrives. I often picture a bunch of sneaky soldiers sitting there sipping tea and eating cake off elsewhere in the game world, laughing at the poor player as they wait around in the radioactive rain.

The first game was packed with atmosphere, it was a truly great experience (if flawed) and offered an open-world shooter with its post-apocalyptic disaster feel, varied environments, mercenary factions and mutants. There were some truly amazing sequences in that game that rivalled the big budget titles. Clear Sky attempts to capture some of that glory but falls short in some places. I would love to explain the story to you, but it's like STALKER, it's not a great story and the dialogue and voice work leaves a lot to be desired.

A lot of the background voices are in Russian and so you lose a lot in translation, yet I suppose it keeps the flavour of the Zone.

You often feel a lot like your character, lost, knocked out by an anomaly you awaken and meet a group known as Clear Sky. That's about all I can tell you, then it's up to you to go around and work for the various factions and do missions. The world that's presented in Clear Sky feels real, it's the best implementation of an environment like this that I've seen since STALKER. There are numerous little details from the massive industrial sectors to the little camps out in the wild, especially effective at night.

The world is divided into zones again and there's some loading, just like STALKER. There are guides that can port you around the zone you're in, but there are no guides that can transfer you from zone to zone. There are also a few niggles that shatter the immersion, certain slopes that are a gentle incline but still can't be climbed, fences that you can't cross and the like.

What is impressive about STALKER: Clear Sky, when it works, is the various faction wars that happen throughout the game. These give a sense of reality to the Zone and can picture a bunch of enemy soldiers that suddenly lay waste to an opposing faction's temporary HQ and try to kill the defenders, should they succeed they will immediately occupy that territory and begin to defend it against all comers, including you.

This isn't just side-dish stuff, these faction wars help reward the player with a sense of accomplishment as well as in-game rewards. Flush the enemy out of a zone and you'll have an easier time of it; you'll encounter friendly patrols that will help out and so on. This is really where games like this shine. You can find NPCs to trade with, access sub missions and other elements that make the game more interesting. The major gripe I have is that the triggers are often bugged, so you're out there waiting for a war to happen and it never does.

Clear Sky has been beefed up in terms of combat as well, the enemy AI has been polished and now they have a ninja-like ability to land a grenade right between your eyes even in the dark. Hopefully they'll tweak this to be a little more realistic in coming patches. A firefight with a few guards and so on is a challenge, a full scale gun battle is a nightmare and extremely exhilarating as the enemy now use cover and concealment to their advantage far more than in STALKER.

The weapon upgrade system is back and it's a huge cash sink this time around, you'll spend ages taking every weapon and min/maxing it to the best potential only to realise that you've got to hunt around for more ka-ching. Artefacts used to be a good source of funds, they were littered around the original STALKER like candy in a store that sells sweets, seriously, and you couldn't move five steps without finding one. Now in Clear Sky you'll find them and they'll be in dangerous areas, making each one a real hazard to get.

There are some really unforgivable bugs in the game, NPCS will vanish at random, not just one or two...but a whole region will disappear and refuse to return. That's right; everyone will just up and vanish into the ether. I've had this happen twice now and a quick poke around the net confirmed that it's not just me; several other gamers and even reviewers have experienced this problem. We are not alone (except when the NPCs vanish).

Bugs aside, the game has a visual presentation that makes it a treat on the eyes. It's the attention to detail that drives STALKER: Clear Sky, from the expressions on the faces of the NPCs, the mutants, the rabid dogs, the whole damn world that unfolds as you travel from place to place. It's brought to life with vibrant (if somewhat gritty) graphics and tremendous sound. Dawn, day, afternoon, evening, night and so on, all of these are presented with a gorgeous amount of graphical oomph, they flow seamlessly into one another and being under the stars even in a fierce thunderstorm is something wonderful.

We turned off the dynamic music after a while because it ruined the rest of the sound effects, the gun battles were truly stirring and the various spot effects were tremendous and added to the immersion right away.

STALKER: Clear Sky is one to keep an eye on, a few patches down the line it should be something like the original STALKER, but for now it's far too buggy to stand as it is.