The game is presented as a side-scrolling beat'em-up/platformer. The level design is only "decent" from the perspective of what it demands of you as a platformer, but there's a neat, little destructive element to all of the environments that let you feel like the Hulk.
Controls are all mapped to the D-pad and buttons -- no touch-screen stuff shoehorned in for poor measure. Enemies are placed in mostly static positions, though that's not to say they offer no challenge. In that regard, the game plays almost like Xevious, forcing you to avoid scattered enemy fire.
The fun for me was in simply navigating through each level, being able to super jump with Hulk strength and pound foes. When you slam down upon an enemy, they'll go flying across the screen, often into another enemy to create a chain reaction of simple awesomeness. The overall experience is kind of shallow, but tight controls and action make The Incredible Hulk for DS an enjoyable romp from start to finish.
There's a small handful of costumes to find along the way, but that about sums up the extras. If you're into arcade-type gameplay, though, you might have fun playing through the story mode additional times. There's also a mutliplayer option, but each player will be required to have their own copy of the game.
The sound elements are pretty cool as well, and the graphics are a nice treat, with fluid 3D animation. There were some real chug moments with the framerate, however. Considering the various smoke/mist effects and explosions, the visuals are still fairly impressive. The music is mostly good stuff too. The themes seem to fit this particular Marvel character quite well. The Hulk has a small selection of roars and utterances that oughta elicit a bit of fanboy nostalgia here and there.
Overall, it's a decent, little package. The game isn't going to blow anyone away -- it's more of guilty pleasure for Marvel fans -- but the tight mechanics and level design make it a respectable option for anyone into action-adventure games. Since you're likely to find it dirt cheap these days, there's also little to feel guilty about.