Some great set-pieces and a unique setting are squandered with imprecise gunplay and cliché level design.
The story centers around the infamous Pandora's Box. According to legend the gods gave Pandora the box as a wedding gift, but she was instructed never to open it. As we all know, curiosity got the better of her and she opened it, unleashing all evil into the world. In Legendary, the Council of 98, a secret society, was formed to hide the box in order to preserve humanity against it. It was hidden so well, that even the council forgot about it's location, until now.
The story opens with Charles Deckard, a professional thief for hire, breaking into a New York museum to steal Pandora's Box for LeFay, a member of the Black Order, another secret society. Upon discovering the box, he use the key he was given only to realize that he was tricked into opening it. As the monsters are unleashed into our world, Deckard's hand is branded with a signet and not too soon after LeFay's men arrive to kill him. The Council of 98 find Deckard, and together they set off to correct his mistake.
While the story gives a good backdrop to the action, it's not terribly interesting. You all ready know all the stops, what the villain is after, etc. The only thing you may not expect is the ending, which when compared to LeFay' actions, makes Deckard look like a hypocrite. Besides if he could do that all along, what was the point of the game?
While the story wasn't particularly memorable, the set pieces and enemies arrayed against you are. The opening sequence when you open Pandora's Box is one of the most amazing I've seen in a game. The sheer amount of carnage, death, and special effects on display are astounding. This is helped along by superb boss fights and unique enemies. While I won't blow any of the bosses, I will say you'll fight Nari, Minotaurs, Werewolves, Griffons, and more.
What makes fighting these enemies so unique is their actual design. Nari, fairies of dead children, aren't actually in our dimension and thus can only be damaged when they enter it. You can use your Animus (more on that later), to force them, which adds an interesting layer to the fights. The game uses them well outside of combat as well, such as stealing parts you need for a generator, or merely killing everyone in gruesome ways (that fan kill was shocking).
Probably the best enemy is the werewolf. The thing that makes them so fun to fight is how dynamic they are. They constantly move around and jump from place to place. They keep you moving too by throwing junk at you and flanking. After "killing" a werewolf you have to decapitate it in order to prevent it from regenerating. This makes fighting packs interesting, as it's common to forget to decapitate one and get surprised unexpectedly. Dare I say that Legendary has some of the most unique enemies in a FPS for a long time.
It's a shame that the shooting is so poor. You have a selection of a few traditional firearms, blatantly named Pistol, SMG, Assault Rifle, and so on. Early weapons are practically peashooters, and you might as well stick to your axe. Things pick up when you get the shotgun and HMG but enemies get tougher at the same time and the increase is unnoticeable. For example it takes nearly 600 HMG rounds to kill a Griffon. If you have a rocket, it only take one shot. I have a hard time believing that 600 HMG rounds would not even slow a Griffon (no matter how big, those bullets would penetrate). The weapons also suffer from being rather imprecise and bullets never seem to go exactly where you wanted them too. This imprecise feel combined with the weak feel give weapons an overall mediocre quality.
Something helps make up for the shooting to an extent, and that's Animus. After being branded with the signet, Deckard is able to absorb energy from dead enemies and utilize it. He can heal himself, or he can weaponize it into a pulse. The Animus to heal is a nice balance between traditional health packs and regeneration. Also it now makes killing enemies doubly important to your survival. It's very well done.
As for the pulse, Deckard can shoot out a brief flash of energy capable of killing enemies. However the Animus Pulse's more unique features show when you experiment. For example Animus can be used to transfer Nari to our realm, or decapitate werewolves. More common uses could be simple damage dealing, and if surrounded the pulse is good at knocking enemies back. It's fun to combine it with the shooting. It may be simple, but it's well done.
Graphically the game is, as Kevin VanOrd says, ugly. While there's some great art style here and the environments are truly massive, everything else is rather poor. Lighting, shadows, blood, and water are all so low resolution that they're pixelated. Textures are rather bland, not helped by the poor color palette which makes everything gray, gray, gray, oh and a little brown. The graphics are rather glitchy as well, with some flickering and tearing, not helped much by V-Sync. Foe an engine that usually looks good, Spark sure screwed it up.
Sound Design is equally disappointing. While monsters and music are strong there are plenty of problems. The music, while of high quality, isn't very fitting and undermines some of the game's atmosphere. Firearms sound rather generic. Voice-acting is the biggest disappointment, it's main problem being lack of actors. A few parts sound as if the entire level was voiced by one man.
In the end, Legendary is an average, by-the-books shooter. While it has some stunning set-pieces, interesting enemies, and a cool animus mechanic; poor shooting, level design, and graphics really hurt it. If you're interested in Mythology it;s worth a look, otherwise it's safe to pass on it (it's pretty cheap now though).