Multiple problems.
I've been having some real trouble with careful pixel placements. I haven't seen anyone else really come across this problem (Or maybe I haven't looked hard enough), so I assume there must be some common practices used to eradicate these demons.
The trouble I've had explaining this to so many people now. I can't put it in words very well, so I'll use pictures, instead.

What I'm currently trying to solve is adding a fine highlight (specular?) on the top left spike in the last (wip) frame there. But the line providing the symmetry through the spike has quite irregular steps, making this a bit harder. That is where I'm trying to add the highlight. Refer to the other frames if you still don't know what I'm talking about.
I can't seem to make it look good and smooth without distorting the form of the spike. I think I may have to add a(n) extra color(s)?
Here are some failed attempts:

Maybe I'm being too nit-picky? It's just an animation frame to go in-between the other two key frames.
Now that I'm looking at it, I also fear the spike is too large. I've been having trouble with that as well; trying to get the size and shape right for the spikes, whilst avoiding jaggies, and irregular steps as much as possible.
Also, in the first complete frame there, I feel the top-left spike (what is it with that god damn top-left spike?

) looks too flat, and I have no idea how to remedy this problem either. I've been toying with it a lot. Both of the sides are meant to receive equal lighting.

One more thing; I suck at choosing colors. I honestly can't tell what looks good and bad. I'm not color blind, but I just don't know. I thought the orange looked alright for the eyeball color, but then I also thought, "Meh, too mono" and changed it towards another warm hue, a lavender color. Also toyed around with some other purples, you can see that in the first image. What do you guys think? And yes, I plan on using mainly warm hues for enemies and colder hues for 'good' sprites, it is for a game. (One of those top-down, scrolling, space-shooters.. like
Tyrian.) Good idea or not?
Also, while you're here, I'd also absolutely love any kind of crits or comments on anything you see.. please.
Ugh, I am so long-winded.
(this looked kind of cool.)