What a great game! I have to tell you, even if you were not impressed with the demo, please don't give up on Far Cry, possibly the most complete single-player FPS game to come out since Half-Life (and no I didn't forget about Halo!). I am a PC-only gamer with a focus on FPS games. I am a very big Half-Life and Unreal series fan, both single-player and multiplayer.
Just a note about the version that I am using: When Far Cry was first released, it employed an autosave feature that many game developers use today to keep the "shoot-and-save" style of gameplay at a minimum. Unfortunately, as is the case with many games, the community at large started to complain, and patch 1.2 was released that added a quicksave feature, among other things. However, the 1.2 patch was very unstable with certain graphics packages (mainly ATI, I believe) and was quickly removed from official distribution and support. Another patch is supposed to be on the way that will add quicksave features and be the official patch.
I purchased Far Cry on the day before the 1.2 patch was released. My Nvidia 5900 XT was new at the time, and I had trouble getting the game to work correctly with the latest driver release from Nvidia and Far Cry's 1.1 patch. When the 1.2 patch was released, I grabbed it right away and the game worked perfectly with no problems at all. Imagine my surprise when the 1.2 patch was recalled! Because I had no problems with the patch and most Nvidia users need it to get good performance, I decided to use it when playing the game, even though it doesn't have official support from the developer. I have never used the Quicksave feature that this patch added however, so an ATI user with the 1.1 patch should have virtually the same experience that I did. If you really need the quicksave feature, I would suggest that you play the game at the next difficulty down or wait until the next patch is released. Nvidia users will probably not have any problems running the patch, but do not buy this game expecting to be able to use it as it is not official anymore.
Is the quicksave feature necessary to have a fun gaming experience? In this case, I don't think so. There are plenty of autosave spots in Far Cry to keep you moving through the game, even on the hardest difficulty. The inability to restart from ten seconds before you got hit makes the game much more involving and tactical because you must survive the whole battle at once, not just parts. I would strongly suggest not using "shoot-and-save" because it will detract from your experience of this game. Okay, on with the review!
Gameplay: This is one area where Far Cry really shines. There are actually two distinct types of play that you need to use, one for the extended indoor areas and one for the very well done outdoor areas. The indoor play is more standard FPS fare with drawn-out firefights that depends on weapon management and quick reaction time, and will be instantly recognizable to any FPS fan while being well enough made to still make them enjoyable. Fortunately, the bulk of the indoor areas end just about the time you start to get tired of them.
Gameplay in the outdoor areas is a mix of jungle stalking and vehicle-based assaults, with the latter being effective only when used carefully. The jungle fighting becomes easier as soon as you realize that the AI can't see through the thicker bushes. But this also makes it hard to keep an eye on your opponent while diving into the darkest woods whenever you hear a sound. The best tactic is to take it slow and try to see them and set up an effective attack (usually from a distance -- there is nothing like taking out two or three guys in a few seconds with well-placed headshots) before they see you and take cover. Actually, sound plays a very important role in this part of the game, allowing you to tell when enemies are getting near and if they have been alerted to your position. Most of the time enemies come in groups, which is where the vehicles can come in handy, by allowing you to take out the most dangerous target (a rocket boat, for instance) before ditching into the jungle to find cover.
On the higher difficulty levels (I played on the middle one the first time, the hardest the second) the ability to effectively use cover to keep an enemy pinned down from a distance is necessary to complete the game. Another thing that really makes the game work well is the enemy strengths/weaknesses, described more below in the AI section.
Physics: The physics engine doesn't affect Gameplay that much (besides vehicles), but it does make the game look much more realistic and lends a huge helping hand to the immersiveness of the game. In fact, the only thing I wish they had done differently is make the physics more integrated into the gameplay.
AI: This is one area that Far Cry does very well and is one large reason that the game feels like Half-Life. Enemy soldiers are smart enough to see you very easily, and once they shout or shoot at you (or you shoot at them with a non-silenced weapon), all other enemies are on full alert and headed in your direction. If you manage to sneak around silently, you get the idea that they are expecting you. There is no time when you can kill every enemy in a level without their being aware of your existence. Even if you have a silenced weapon and take your time, they still get worried and start to investigate although not on full alert.
Others have complained that the AI is TOO alert, but I don't think this is really a problem. The enemy AI is most impressive in the open jungle, as you will hear them shout and execute flanking orders that make your life very, very hard. The other enemies in the game are more or less dumb animals, and since that fits in with the premise of the game, it's not a problem, although you will probably not have much of a challenge dispatching these types of enemies.
The soldiers are the most rewarding to fight and the different levels of body armor that they carry is more than enough to spice up the game, as well as the fact that some of the enemies will come to you when alerted and some will wait for YOU to come to THEM. In the beginning of the game, it's very effective to stay at a distance and pick them off with headshots, but as you come across enemies with full body armor and even riot shields, chances are that you won't be able to hurt them unless you can put enough lead in the armor to push them off balance and then get a shot that counts. I believe it is possible to kill these enemies by shooting through the armor, but you will soon discard this as a tactic because you will not have nearly enough ammo (or time) to do this with 10-15 enemies of this type, which you have to do several times near the end of the game. I enjoyed these sequences more than any in the game because of the different strategies that you have to use to effectively to dispatch elite soldiers of this type.
Graphics: Just look at the screenshots that are in this review or what you can find on the web and you will get a good idea. Probably second only to Doom III at this point in time. I am able to run at High detail levels (one from the highest in most areas) in 1280x1024 at 40 fps or better.
Positional sound: Because I was playing the game with headphones I only used stereo sound, but I still got the impression that I could tell where enemies were coming from. The time when you use this most is in the jungle when alerted enemies are searching for you. Hiding in the bush, you can hear them slowly advancing, snapping twigs and stepping on leaves as they go. The challenge is to be facing EXACTLY the correct way when they burst through the foliage so that you kill them and not vice-versa. I didn't have much of an issue with this unless two or more enemies were really close and it was hard to pick out one from the other.
Storyline: Buy the game. It's a good story, which is another element that is like Half-life. However, this game does have distinct levels which usually consist of giving you an entire island to explore. This allows you to more or less approach the goals in whatever fashion you think is best and in many cases, from whatever direction you think is best.
Closing: If you are a hardcore FPS fan or even a casual player, chances are that you will enjoy Far Cry.