There is a very close evolvement of his games earlier on, going back to Earthshaker in fact. I'm surprised it hasn't gotten mentioned yet, but ES resembles WW in almost every way.
Earthshaker: main ramp scores 1/2 miles, scores 50-100K per ball. Side ramp scores 3 miles. Extra ball at 2 different mileages, special when on-pf mileage indicator fills up. Ramps score 200K at 99 miles. Consecutive main ramps build up captive ball to quick multiball. In quick multiball, shoot side ramp for 1M (only one though - but 3rd one also awards extra ball). To light main lock, must complete all lit zones. Bonus x (including eb and special awards) based on locks lit. In 3-ball, shoot ramp to light jackpot, shoot side ramp to collect (only once). No jackpot? Shoot scoop for restart (this goes back to Banzai Run). Jackpot awards on speaker panel. Mystery award always available on scoop.
Whirlwind: main ramp scores 1/2 tolls, scores 50-100K per ball. Side ramp scores 3 tolls. Extra ball at 2 different tolls, special when on-pf toll indicator fills up. Ramps score 200K at 99 tolls. Consecutive main ramps build up drop target to quick multiball. In quick multiball, shoot side ramp for unlimited 1M. To light main lock, must complete all lit compass arrows. Bonus x (including eb and special awards) based on balls locked. In 3-ball, shoot side ramp for jackpot (million+). No jackpot? Shoot scoop for restart. Mystery awards on speaker panel. Complete all awards for cool bonus. Inlane or upper flipper ramp shot relights mystery award.
Funhouse: main ramp scores 75-150K per ball. Everything on pf advances towards multiball. Quick multiball is only a mystery award. In quick multiball, shoot upper flipper shot for unlimited 1M. In 3-ball, shoot upper flipper shot for jackpot (million +). Shoot ramp to relight jackpot. No jackpot? Shoot hallway for restart. Mystery awards above scoop. Complete all awards for cool bonus. Inlane or upper flipper shot relights mystery award.
I think you can kind of see where I'm going with all this. I could easily do the same with TAF, TZ, and NGG. Heck even Monopoly and RCT mostly. There are many similarities and evolvements as time goes on, not a bad thing, but very obviously related.