Quoted from NicoVolta:Centaur is great... I just can't decide if Medusa is better or not. Need to play more to be sure.
Fathom edges out Centaur and EBD for me because I get two paths of in-line drop targets (one of which is awesome to hit across the top), a spinner, multiball (though Centaur's 5-ball is insane for '81!), two rows of drops, and just a beautiful unusual theme.
Flash Gordon... damn. Hate that sumbitch. Such cool art. Such unforgiving gameplay. Really, the game should either give you a credit when pushing start or pop open the coin box and punch you in the stomach at random.
I actually don't enjoy Medusa very much. Some cool ideas, but I've never enjoyed shooting it.
As for Flash Gordon, I have often had to question if I like the idea of a game that punishes you even when you *make* the shots that are ideal. But then I drop another quarter in it, so I guess the answer is "yes" and thus my internal questioning is pointless.
Looking at the list, I actually have no memory of ever playing Embryon. Surely I did somewhere, but I don't remember it.