Metallica has way more shots. You've got
Fuel shot
fuel targets
Left Loop
Inline drops
Left ramp
Sparky
newton ball
Snake
right Ramp
Right loop
Scoop
Spot targets
All very challenging and fun.
IM is a faster game for sure, more flow, but way less to shoot at
left target bank
Left loop
War Machine Kickback
Left Ramp
Center Spinner/Monger
Whiplash
right ramp
right loop
right target bank
spot targets
I also like Metallica's rules, I would consider them pretty deep. IM has a good wizard mode but not as deep as Met.