It's been done over and over, a movie game that isn't a disaster, but isn't even good, it just is.
It's an RPG, without leveling-up or currency. It's story-based, except you almost certainly know the story. It's got action, but no real replay value.
Story: If you're bothering to read this review you almost certainly know it. But for the 1% of you who don't, I'll spell it out anyway. Peter, Susan, Edmond, and Lucy Pevensie are sent to an ancient mansion during the air raids of World War II, and they (Read: Lucy) find a wardrobe that leads them into a world known as Narnia. Originally penned by C. S. Lewis, the game started as a novel, was made into at least a few movies, and the most recent movie had a game based on it (Based on the movie, not the book). The game does a fairly good job of recreating the story, though like all games do it takes several liberties with the script (A chase through Boggle tunnels, a battle where Susan takes on a pack of wolves, or Edmond's epic foiled escape from prison) which don't detract from the experience, and actually add some length to a game that can be finished 100% in a matter of five hours with the levels. Those who feel that it adds too much to the books should be on the movie's case more anyway, and those who feel that it derails from the movies should read the books first.
Gameplay: It's a hack and slash RPG, without the RPG in it. You run around with a predetermined character using their assigned weapon to beat up enemies, though you really don't need to, you can regain health from beating them but you get more by avoiding them, and since there's no real motivation to fight, why bother? Other then that there are some puzzles, like figure out which direction you can push the rocks so they move, run fast enough down the icy lane so you keep your flaming wooden sword burning long enough to melt the ice wall, or find out just how you're supposed to beat the invulnerable boss. Many things are overly complicated merely to make you take longer then you have to, and only one of the bosses is actually fun (The one you don't need to really think to beat, just slash, heal, and repeat).
Of course, you have very little health, and it doesn't recover automatically. Instead you must recover is by eating candy, cookies, and sandwiches, of which only sandwiches refill as much as the instruction manual claims they do (The others do about half as much as they're supposed to). You can find items lying on the ground, in chests, or inside of destroyable objects like tree stumps, mushrooms, and ice statues. Such items are the only thing you carry from one level to the next, or can take to the beginning of the game after making it much further.
Besides health, you have two other meters to worry about. The first and worst is temperature. Somehow heavy coats to wear don't protect you from low temperatures, and as
long as you're not next to fire you will slowly get colder, and getting too cold causes you to periodically shiver and lose HP until you die. Somehow it doesn't apply in the White Witch's frozen castle, but does apply during the great frost. And of course Edmond gets the worst of it since he forgets his coat when he runs off to the Witch's Castle. The feature is mostly just awkward, doesn't make a lot of story sense, and would be forgettable if it wasn't so dangerous.
The last meter is even more useless then the previous one, it's the call for help meter. Once it fills up (Apparently from fighting enemies enough) you can call a sibling/teammate for help and they will appear, assuming they weren't already next to you. Hardly ever going to help you, and the 1% of the time it could benefit you it'll certainly be empty anyway. I played through the whole game twice and never used it more then once the entire time, it's that forgettable.
For those who wish to fight the enemies, you're in for a rough time. Most of the foes at the start die easily, but as you go on they get more and more powerful while you don't until late in the game, and by then all the enemies get upgraded more. You only get one basic attack per character. At first you have Lucy, you kicks the enemies to death (You start out fighting weasels), then you use Edmond and his more powerful punches to lay the weasels low, then you get the best character in Peter, who uses a powerful sword, to take down new enemies like Goblins and wolves. You get to use Susan mid-game, she can only toss weak snowballs from a distance, and she is absolutely appalling at close-range combat since she has no melee attacks, which is made especially bad when she's forced to use it towards the end of your time as her. After that you cycle between the other three siblings until they finally get upgraded. Peter and Edmond now use swords to attack with, which are far better then their old weapons, and Susan gets her bow and arrows to attack with, except you are no longer able to play as her. Lucy gets no new attack but her only remaining level features old enemies anyway, and she's accompanied by the upgraded Susan. Upgraded characters do get a powerful charge attack to use, but they can't move once they start charging it, and unless the enemy is dumb enough to move next to you or is even dumber and doesn't attack you when you charge it up next to them, you're going to do no good with this new attack, so it's useless except for a fancy display of weapon usage. Finally, upgraded Lucy gains the ability to stand next to enemies made out of stone and call Aslan to free them, not that it helps any since they won't accompany you in fighting, they're just necessary to beat the level.
Much better for battle are secondary abilities, these are gained as you progress through the game and allow certain affects to be accomplished. Some are only useful in the level they're given to you, like the ability to call for animal friends near animal tracks or the ability to lift certain boulders. Others are not necessary to beat the game, and instead give you an advantage in battle, like refilling your warmth meter, driving the enemies away for about two-fifths of a second, or calling your siblings together for a powerful charge attack (Which is of course unlocked late in the game). Of course, neither armor/weapon upgrades nor new secondary abilities are available when you return to previous levels.
Characters: Besides the Pevensies you get multiple characters from the series to accompany or fight you throughout the game. Mr. Beaver comes with you in several levels and can actually fight, Mr. Tumnus tells you semi-helpful information (Like "The weasels are enemies") in the beginning of the game, Aslan appears to do nothing besides get killed in the classic scene, come back to life, free the stone friends, and kill the Witch after you beat her in a long, tedious duel. Finally several animals (From foxes to bears) assist you in the final battle since your siblings are all off someplace else. Enemies range from weasels and goblins to boggles and wolves to Minotaurs and giants, as well as some unidentifiable creatures that don't seem to be quite finished in design. And there are five bosses in the game, four which require you to do something then attack them or attack them then do something, and only one of which is just hack and hack until it dies. Expect to die quite a bit before you beat them.
Difficulty: There are three available difficulty settings in the start of the game, easy, medium, and hard. In more difficult modes the enemies do more damage, take more to defeat them, and that's it. No bonuses for you what so ever. Brutal difficulty (The game's only true unlockable) is even worse, enemies like giants and Minotaurs can kill you in one to two blows while it takes you a lifetime to beat them, so you might as well not bother.
Unlockables: There is only one sidequest in the game, and that is to find all of Mr. Tumnus' lost artifacts. Each one has a bit of information about it, and it's actually sort of interesting, at least the first time. Once you have them all you unlock the almost impossible Epic difficulty, and that's not a spoiler since even the instruction manual tells you how to unlock it. Other then that, you can gain new abilities as the story demands, but as explained before they're not able to be taken back into previous levels, so what's the point?
Technical Details: The graphics are average to above average; you can read the words on-screen without difficulty and effects like snow don't slow the game down. Of course, nearly everything being white, black, or brown might contribute to that. There is no voice acting, and the sound effects are just enough to get by (Sword slashes on body, sword slashes on armor, spear hits character, and the best of all: Shatter ice statue). The music is equally passable, some of it sounds like it's out of the movie, and some of it is just, there.
Multiplayer: You can play with a friend in any level after level three, since the first few had no one you could play as anyway. This is the only way to play as characters like the brown bear, Mr. Beaver, the little fox, and Susan with a bow and arrows. It's unknown just how Edmond's solo levels work out.
Replay Value: After you play through the 17 levels you can go hunt for Mr. Tumnus' lost artifacts if you care for useless trivia, or you can just beat the game in under a week and (Hopefully) return it to where you bought it from for a refund, you won't really care to play it again, even if a friend also has the game and you can play multiplayer.
Final score breakdown:
Story: 7/10
Gameplay: 7/10
Graphics: 7/10
Sounds and Music: 6/10
Fun: 6/10
Replay Value: 4/10
Pros
Shattering ice sculptures is fun
The most important scenes are intact and don't look half bad
One boss fight is actually fun
Extra fights to gain EXP aren't necessary
Cons
Puzzles are unnecessarily confusing
Harder difficulties are a waste of time
Fighting is pointless
Upgrades are just there, they don't really help you out
Only a couple of really fun levels
You're going to miss the ability to gain EXP and get more powerful
Overall:
6/10
If you're looking for a purely average experience, look no further. If you want the Narnia story then watch the movie, or better yet read the book (And then the rest of the series). And if you want a good hack and slash RPG on your GBA, just look elsewhere (I have better ideas if you wish to know them).