While a few things could have been improved (namely, the horrendous cutscenes), the game manages to stay flashy and fun.
Where the game goes a little wrong is definitely with the cutscenes. The animation there is horrible, so bad it hurts the eyes. The backdrop or backgrounds are bland, and the voice-acting terrible.
Another point worth making is that the game could have used a better character design -- as in their superpowers and how they play out in the game. The mechanics are pretty good, but a few of them seem like they could have been better, namely Batman feels a little flat.
Similarly, the shield system could have been fleshed out a little more. Basically, you collect shield icons by accomplishing objectives or bashing things or finding them in the environment and then subsequently use them to unlock extra content. The complaint: the content could have been better. Apart from unlocking new heroes to play, the brunt of what you can unlock are alternate costumes for your caped crusaders... and most of them suck. On top of that, although there is a host of cool heroes to collect, like Huntress or Aquaman, there are something like 3 or 4 extra Green Lantern heroes per say you can get. WHAT"S THE POINT!? One is enough. They could have taken a few Lanterns out and put in other heroes instead, like the Hawkman or Nightwing or the Atom (which would have been really cool).
But despite these shortcomings, the game still scores at least a 7.5 in my opinion, and is well worth playing. The in-game graphics, as mentioned, are good -- no, great -- and provide just the right counter-balance to the awful cutscenes. The game itself plays well with your standard assortment of action RPG conventions from kicks to punches to combos to superpowers. And, additionally, the story and levels themselves are diverse, creative, and just plain fun, from battling giant 1960's sci/fi robots or mutant insects bent on conquering the world, to duking it out with nefarious ape-men straight out of the Planet of the Apes and so on.
Altogether, sure the game has some wesknesses, but it's pretty good.