I'm not a fan of the game personally, but I get the impression it's partly do to the way the modes are designed (they seem to be a bit more complex than just 'this shot is worth tons of points for the next 30 seconds', although I'm not super familiar with them), as well as the multiballs. The prison multiball, despite having a bash toy for it, requires you to first bash it some, then choose between hitting shots or bashing it (bashing is dangerous, but easy, shots are harder to hit, but will get you done faster), and then once you get to multiball, the rules are, again, a bit more complex than some games, as you have to hit shots, then go back to bash the doors, instead of just, say, 'all shots are lit for jackpot'. The bloodbath MB on the drops is also a less 'stardard' multiball, both in how you start it, and the rules (I can't think of any other add-a-ball focused MB besides Centaur?). The skillshot is also slightly more complex than normal. Maybe the well walker has some extra little things in the rules, but I'm not sure, I just hit it over and over.
Basically, most aspects of the game seem to be slightly harder, and require more thought, than the 'common denominator' games. Although I can certainly think of specific aspects where other games beat it, those games generally will still have some simpler aspects as well.
Metallica, similarly, goes a bit beyond normal games with some of the features, such as the way you collect items and qualify hurry-ups, or the rules in some of the Crank It Up modes (I've heard people say Enter Sandman is the coolest mode in pinball).
Spiderman, to me, feels like the most basic, lazy code you could have (except for the shot multiplying rules, but they're also not very clear). Start a mode? Shoot all the shots. Modes? Shoot all the shots, frenzy, shoot this specific shot a lot. Start multiball? Hit a target, then hit an orbit, or just shoot Doc Ock repeatedly. Multiball rules? Shoot all the shots. Villains? Shoot the villain a whole bunch to start them, then shoot them some more. I'm probably doing the game a bit of a disservice as I don't play it much (because I think it sucks) but that's my general understanding of the rules. It has good callouts?