I got to hang out with O-Din recently and got to play his Struggle Buggies, the space in between the flippers is like 8"
Other honorable nut kickers are...
WOF-brings necessary nudging skills for a modern machine
IM-Brutal at times
AC/DC-Kick you in the nuts
Ghostbusters-Bust your balls, you have to adjust play for flipper gap
Tron-The timing for left upper flipper tough as hell