I've been using Pyxel Edit which also has a preview window. Just have to pay more attention to 1x preview.
No problem, my friend. I like to use a program that allows 2 windows open at once so I can have one at pixel level and one at 1x. I think most programs can do that. Even mspaint had that option. It's not necessarily a rule that you have to, but it has really been helping me to improve in my art since it was suggested to me, being able to see the changes at the pixel level affecting the piece in real-time. I hope it helps. 
Thanks. Very kind of you to give constructive criticism. I kind of went back and forward with two colors for the nose and the mouth but didn't pay enough attention to how it looks 1x. Thanks for pointing that out. 
It's nice pixeling, but you might give some thought to the contrast of the nose and mouth. They are very close in hue to each other and, at 1x, aren't very distinguishable from one another. I know it took me awhile to use more contrast in my pixeling so I don't want to see someone else stuck where I was if they don't have to be. 
It's a great job, though, and I hope to see more from you soon!
With the right lighting probably wont really need those lines as well, just hints of lines from the shdowing