A good time killer and a very pretty one to boot, but that's all it is.
When you first start the game, you'll probably be overwhelmed with positive emotions. The presentation is really great. It's not just about the graphics; sound and animation are also of high quality. Humans look and move realistically, explosions and particle effects are abundant and also look great, and Akrid, alien monsters, are particularly well done. There are several different kinds of them, ranging from small flying creatures who attack in packs and die from a single bullet, to huge wormlike monstrosities that require an arsenal to be brought down. They all are greatly detailed and animated, up to the point of being believable. Definitely the best aliens I've seen in a game.
The game is additionally livened up by by a number of nice graphical and gameplay touches, such as various blizzard and snow effects, your character losing balance when a big alien emerges from the ground nearby, the Akrids freezing solid and then shattering to pieces when deprived of thermal energy, and so on. It all adds up greatly to create a very exciting, hollywood-like experience. You will often be amazed at just how great the on-screen action is.
But when you complete the first couple of missions, you'll start noticing that there is not much to do except blasting everything and going from point A to point B. That is still exciting, but with time becomes somewhat tedious, as there's not much skill involved in fighting (as long as you have some thermal energy left, you are almost impossible to kill, and you will not have any problems with energy as long as you don't stand still. That's true even for the hardest difficulty settings) and your character movement speed is far from fast.
You'll start encountering human enemies, different kinds of Vital Suits (which are basically mechs that you can pilot), enemy VSs and occasional simple platforming sequences, but all this isn't going to change the fact that the levels are very linear and there is nothing to do except shooting and running.
There is another thing that substracts from the game. As your supply of thermal energy is constantly depleting, you'll often be tempted to just run past enemies without engaging them, and nothing is stopping you from doing so. Sometimes it goes to the point where you can finish entire level just by running through it paying little attention to the enemies. That leads to an obvious question: what were developers trying to accomplish by making their game emphasize on combat this much, and then giving the player great incentive as well as all the means to just skip it?
That's not to say the game becomes completely boring after a while. The boss battles are exciting throughout the game, and core gameplay remains entertaining, if only thanks to amazing presentation. The problem is that game doesn't have any depth to it. You see that when you finish like third or fourth mission and know exactly what to expect of the rest.
In cases like this, a good story may actually save the game by giving players a reason to play it to the end. It doubles with Lost Planet, as the game tries to be story-driven, with cutscenes after each mission, plenty of dialogue and a cast of somewhat RPGish-looking characters. Despite all its efforts, the story starts to show its weak points almost right off the bat. It tries to be dramatic, and fails, partly because of uninspired dialogue and partly because of some noticeable gaps. The worst part is that it takes itself very seriously while occasionally presenting you with almost nonsensical lines, which makes it very difficult to empathize to. Well, I'm not going to pretend that I'm a good critic, but when after a long drama-filled cutscene you are simply told to "go out there and destroy snow pirates' base", and you actually go and do that, that's not a sign of a good story.
To top it off, there are some port-related issues with VS controls and multiplayer games. I don't know about multiplayer, maybe I can't see any games just because no one is playing yet, but as for VS controls, the defaut keyboard setting is really broken. The fact that all tutorial screens show you only Xbox 360 controller button layout doesn't help either.
All in all, this is a good game, but not one you will remember after finishing. Its many weaknesses just can't overshadow its great presentation and excitement of tearing apart alien bugs. If anything, this game is worth playing just to experience next-gen graphics on your PC.
Although to truly appreciate its graphical greatness you'll need a fairly modern PC. If you plan on turning most of the settings to high, your system must have no less than a dual core processor, 2 GB of RAM and NVidia 8800 graphics card.