Quoted from ForceFlow:The speech board is very difficult to find.
Otherwise, I think all the other boards can be sourced as either originals or aftermarket options without too much trouble.
The only serious parts availability issue that I can recall is with with the ball lock mechanism since it's unique to that game. Everything else uses fairly universal classic stern game parts.
Plastics and backglasses are available. Cabinet stencils are available. Playfields are not available.
The ball-walker is on Freefall as well (admittedly not a common game!) but honestly it's such a simple mech that I can't imagine it breaking. Of more concern is the giant drop-target bank (found in Meteor and Nineball as well) which can be unreliable or broken (in particular the very long reset-arm often snaps).
Overall a solid game, very fun!