This looks and sounds like it could have been a real game of the era.
The guys popping out of the ground, the worm/snake-thing, reminded me of Super Star Wars, and when one popped out of the side of the wall, I LOL'd because I was not expecting that.
My only suggestion would be to maybe have some optional tutorial text about controls at the beginning for picking things up and for getting through the first door. Also, at the beginning, I threw the seeds over the edge, they broke open, and the inside kind of just lay stuck at the bottom of the screen amongst the black shadows. If possible, maybe items should delete when they're in the black shadows like that.