It's pretty much a ripoff of X-Men: Legends.... the difference is that everything X-Men should have been... this game IS.
I never liked Legends. At ALL. Everybody else thinks it's like one of the greatest games ever, but I never even finished it due to complete frustration and disgust. My friends ask me why the hell I didn't like it since it's such an obviously good game (according to them). I'll tell ya. I was hyped about the game due to the concept (multiplayer superhero action - dungeon crawler style) and the franchise (who doesn't like X-men?) and the really good reviews in the gaming magazines.
But in execution, it was total disapointment. The characters were too damn small, the graphics were shitty. The characters look almost like Super Nintendo quality characters. I constantly lose track of where I am onscreen because of the aforementioned shitty graphics, poor lighting engine, complete lack of character detail and identical costume schemes.
The characters take for FUCKINGEVER to level up. They're tragically underpowered as far as super-powers go. Their actual super-powers are pretty weak and not all that impressive. The super-powers take WAYYYY too much energy to use so you're constantly running out, and the meter takes forEVER to rebuild. And you die too easy.
While I'm at it, I may as well complain about the artistic license they took with the look of the characters. Why exactly does Logan have a 90s haircut?
Now the Justice League on the other hand was designed by Snowblind. Snowblind did the AWESOME Baldur's Gate: Dark Alliance, and Champions of Norrath 1 and 2. The best dungeon crawlers ever to grace a PS2 screen. They write superb in-game lighting and animation code, and JL is no exception. Snowblind went the extra mile with JL and turned what coulda been a good game into a great game.
It's as if I personally sent them an X-Men complaint list and they designed the game with my complaints in mind.
The characters are bigger. The resolution and detail is much better. If you're a character that can fly, you can fly whenever you want, however long you want and it doesn't take anything off your super-power meter (unlike X-Men). It's easier to level up, the super-powers are way better and your health and energy meters refill in seconds. So you're able to constantly use super-powers. What good is a super-hero with no super-powers? If I wanted to just kick and punch people all the live-long day, I'd play Final Fight. Super-powers fucking RAWK.
But what I REALLY love about this game is how much attention and heart went into getting the characters right.
Superman IS SUPERMAN!! When he flies, it's the classic oustretched fist pose and the cape animation is so fluid and smooth! His heat-ray vision works exactly as it should and makes this cheesy 50's era b-movie sound effect. When he blocks, he puts his hands on his hips and sticks out his chest exactly like George Reeves. His physical attacks consist of wild, swinging haymaker punches exactly like the old Fleischer cartoons.
And he can pick up ANYTHING. Superman can pick up a big armored van and swing it like a baseball bat. When it connects, the enemy goes FLYING across the screen. Now THATS how you make a superhero game!
But it's not just Supes. Martian Manhunter flies and moves exactly as he should. He can shape-shift, phase in and out, and use psychic attaks. Zatana leaves purple-pink sparkles in her wake when she flies or punches and yells magic spells backwards with every super attack. Batman's moves and 'powers' are exactly what they should be. The Flash is dead-on accurate. Wonder Woman can even throw her tiara like Lynda Carter.
Snowblind went the extra mile on this game. An old dog lifelong fan of DC comics like me really appreciates it. I betcha Alex Ross probably beat the shit out of this game the same day it was released.