When I first played the SP Demo, I was amazed with what I saw. Yes, it's not a very easy game to get use to at first, but it becomes such an amazing game once you progress throughout the levels. Of course, it's predecessor Far Cry was amazing, but with the amazing tropical environments transforming straight into a cold and dark environment, where aliens are now to take over, it's just such a creative storyline!
Within the gameplay aspects of the game, it's indeed fun. You are wearing a nanosuit, which allows you to use functions which makes you run fast (Maximum Speed), makes you have powerful jumps and punches (Maximum Strength), allows you to be fully protected from incoming fire (Maximum Armour) and my favourite function within the nanosuit, Stealth Cloak. These features are amazing, and the outcome is something of which you will enjoy. Just remember that these features will ease off depending on your energy within the game. Another amazing feature as well is the weapons customization. You get to customize a weapon in any way you feel necessary. You can add a suppressor (If you're the type of player who wants to use the stealth tactics of this game), you can add a sniper scope, assault scope or a reflex site as well. Other customizations are also grenade launchers, types of ammunition etc. I won't ruin it as their are some pretty fun customizations to use. If you think weapons don't damage an enemy soldier to easily then use objects placed near you within that level. These objects can be boxes to barrels, which can have a funny but realistic outcome. So that's another fun feature to use as well. The environment is also destructible as well, you can destroy palm trees, shoot at vegetation, and can bomb shanty houses which have amazing results. That is something you can use against the enemies.
The animation is lifelike, works perfectly with the enemy AI, has different reactions depending on which soldier, and the AI can do common stuff such as cleaning, being lazy (Smoking, going for a wizz in the corner of the house, or can chat with others). If the AI sees an enemy, it will react instantly and fight back. Other AI's will be alerted as well. They may use a signal flare to call for backup, wave their arms or use a radio to communicate for backup. The AI is smart enough to fight against you, meaning it makes it harder for those with little experience of FPS games. In total, the features are amazing. You won't be disappointed.
The level design, in general, is amazing. You will experience tropical environments, indoor environments which have been designed amazingly. Each level is massive, so it will be fun to explore. CryEngine2 delivers this amazing scenery, so you won't be again disappointed with this game.
Alongside the animation comes to physics, which in general makes the gaming experience fun. My opinion is that they should have worked a little harder on the physics for the human AI, it's not very realistic when they fall to the ground. Object physics such as a barrel roll, or the rope physics have proven to work with this game. I believe the physics works fine, but can have a few drawbacks once you play this game over time.
Other than that, if you buy this game, you get yourself a software to use as well, known as the Sandbox 2. This is a map editor to create your own Single Player to Multiplayer Maps as well. You can add music to your levels, to vegetation and animation. There's lots of things you can add. It will take time to learn all of this though, but it's still something you can enjoy!
Overall, great game, but you need a top spec PC! It runs okay on old PC's, but if you have money to spend on a gaming PC, buy it. I recommend it.