Sumptuous graphics and sound; horrible combat controls; poor first "world". The game improves as you progress
World 3 is a horribly hard slug-fest until you get the wraith powers, at which point, the whole game improves right up until the end. After getting the wraith powers, for some reason, the game improves massively - the puzzles seem far more inventive, more obvious, the battles seem more carefully balanced, and on the whole is a MUCH better game from this point onwards.
World 4 is beautiful graphically, wonderfully atmospheric, and excellently balanced - puzzle, combat, puzzle, combat, puzzle, all the way through. Whenever I return to the game, I skip worlds 1-3 and just play world 4 because it is extremely well designed and great fun to play.
Summary: Good game, let down by its combat controls and patchy quality. Rent it first.