Cactus Jack is a really fun game, I enjoyed playing it a long time ago. I really like the artwork (but very much a matter of opinion).

it's a System 3 - so generally bullet proof.

Not sure what in the way of game specific parts are out there though, although the standard Gottlieb consumables are readily available from www.rtbb.com.au (sponsor here).

Make sure all the dancing dudes up the back are there and complete as I suspect part will not exist for them.