There is either a lot of seismic activity in this world or some kind of vertical hold problem.
I just played through it. It's much more visually stable now, at least for me.
I played through and managed 82% completion. I would love to see you continue building a larger world with more features. A Mother Brain battle, and I would like to see ice beam and actual Metroids. A screw attack and morph ball/bombs would be cool, and a way to shoot up. More hidden areas would be cool too.
I guess it's not easy to do that with a 1-button joystick, though...
As it is, I like it already quite a lot. Better than Princess Rescue, even :)