Any of the Bally solid state games from 1979-1981 or so have simple but hard-to-acheive objectives. Most don't have multi-ball, especially not the same multiball rules as Centaur.
Many of them have "non-standard" bottoms with the closest to Centaur being Viking. Paragon, Future Spa, Skateball, Medusa, Fathom, etc...all have unique lower playfields and are quite fun and challenging. Check out some of the classic Sterns as well such as Star Gazer, Sea Witch, and Big Game.