The first Zone of the Enders is all flash, but in large no substance. However, some sound ideas are at work here and the potential is clearly visible, but it wasn't until Kojima took the reins of the franchise that that potential was finally realized. It's more or less fun to play (and look at) on easier difficulties, but nothing more.
Pros: Fantastic mech designs (Jehuty being one of the all time greats), great music and sound effects, fun to move about, flashy combat that is entertaining on lower difficulties, camera is surprisingly solid when in combat, Viola's monologue, solid boss battles, great defensive abilities
Cons: Combat is seriously simplistic and completely falls apart on higher difficulty settings, camera is atrocious when not in combat, Leo is an annoying protagonist, some bad voice acting and poor writing, short length and yet it has highly noticeable padding, doll faces, mostly useless side-weapons