We're drifting off topic here, but the Spiderball was a great idea that was poorly implemented: it moved at the speed of molasses, its controls could get confusing once you reached the cieling, and to compound the problem many of the rooms in Metroid II literally had nothing in them, so you'd wasted the past four minutes climbing the walls and cieling for zero benefit. The idea was superb: the execution was faulty. I find it telling that no other 2D Metroid ever returned to the Spiderball, and that the 3D ones deliberately restricted its use to predetermined pathways.
Additionally, the areas all look fairly identical, and there's no map to help. It's worse than the original, because the original only scrolled horizontally or vertically: this game has caverns up the wazoo, and you MUST hunt down the metroids scattered within them. I also thought that the fights with the metroids themselves were "bleh" at best: too many of them devolve into "shoot missles until it dies" due to the simple AI, and even the Queen goes down easily if you have enough health and missles. Even worse, aside from the Queen there are no real boss fights, just a first meeting with a new metroid, which you will repeat several times before going on to the next model.
To me, II has encapsulated R&D's tendency to have grand and ambitious ideas that were beyond the hardware's ability to realize, a trend which only ended with Super Metroid.
