Eragon is a resoundingly appalling game on every conceivable level.
Simply put, this game is abysmal in every way possible and any gamer should consider themselves ashamed for purchasing this "product" with any amount of money, hard-earned or otherwise (I work in a games store, so that's my excuse). It's shameful that Microsoft passed this game for certification and disgraceful that the games designers didn't stop to pause and think about just what kind of junk they're trying to pass off as a fully priced product.
The story, which is presented in the most dire, in game pre-rendered, grainy cut scenes is an entirely generic one of a humble boy in a humble village and just so happens to save the world from a generic villain via the use of a talking (entirely mis-cast voice acting) dragon that only he can control.
You're thrown into a series of hack-and-slash sequences akin to the earlier, and far superior LOTR games that were released on the previous generation. Unfortunately comparing Eragon to any of the LOTR would be far too generous to the point of total misrepresentation. It lacks any character, charm, programing skills and for the most parts, any gameplay. The game is entirely linear with no choice of character to play, paths to take or attacks to specialise in. The environments in which you'll manoeuvre are almost entirely devoid of anything remotely interactive, save a few smashable crates. There are the occasional times where you may be required to interact with, say, a bell, or a switch to open a door. But that really is about as exciting as it gets. It all just feels totally rushed; a "cash-in" if you will.
It is worth noting that the game is playable in a co-operative fashion, but again this is yet another botched job on the developers part. The second player can drop-in and out at any time, but even then it still isn't fun as player 2 is nothing more than a gimped version of Eragon; utilising the same basic attacks (performed by pressing A, B, A, B, B, B, B, A, A, A...you get the picture) but lacks any magic abilities which makes them even less interesting than Eragon. He may perhaps have a slightly higher melee strength, unfortunately I wasn't interested enough to discover whether or not this is the case. Added to this, co-op can be made very difficult due to the game not allowing either player to step further than a couple of feet away from eachother at any time. This is compounded by a terribly clumsy combat collision system that quite often leaves you feeling as though you're hitting fresh air and therefore leaves you feeling cheated.
There's also a couple of sections in the game wherein you're placed on the saddle of the dragon and left to an insanely repetetive on-rails shooter section that requires you to fly in huge circles shooting at enemies until an energy bar at the top of the screen is depleted. These sections aren't in the slightest bit fun and instantly forgettable. Graphically, the game is very poor and simply screams "PS2 port" with no effort put into improving the aethetics in any way. If the game had ANY redeeming features what so ever it wouldn't be a problem, unfortunately this is not the case.
The audio is similarly unappealing with the same samples used over and over again. The game does have a cinematic score however, but since it's based on a movie and uses the same music, this isnt saying too much. Similarly, as mentioned earlier; the voice acting is atrocious however some of it offers a certain degree of comedic value. I set my character on fire accidentally and all he had to say about it was a nonchalant "I'm on fire." That is the most fun I had through the entirety of the experience.
For any of you out there (like myself) that are obsessed with Achievement Points, Eragon gives them out at the end of every level; 20 on the normal difficulty and 30 on hard. There's also another 100 points on offer for 'exploring' (note the inverted commas) each level and collecting a bunch of eggs. Unfortunately the points depending on the difficulty don't stack so it would involve playing the game twice, something I personally shudder to even consider.
The game is stupendously easy even on the hardest difficulty despite the aforementioned collision detection, and despite them forcing you to play the game again and so in short offers next to zero value for money, especially when considered the game is full price and not a bargain-bin title that you would most likely assume it to be.
In short, this game is completely atrocious and should be avoided by anybody, save perhaps a few younger kids that wouldn't know a quality game if it jumped up and slapped them round the face. By all means rent the game for achievement purposes if the only other option left with your money is to put it into an incinerator.