[Mikhail Gorbachev]

That's a silly response.
When I read 'incomplete,' I reasonably interpreted it as 'I'm going to add more things,' (as is the obvious interpretation), not 'I'm working on improving existing things.' Secondly, if you had everything I said in mind, and you already knew to use more contrast / shade a vertical cylinder with vertical bars, you would have shaded them that way in the first place.

I won't give further advice, since you don't seem to want any, but I hope you use some of the techniques I suggested. At an early level of learning pixel art, learning to get the right contrast between shades is one of the most important things to learn.