Chrome

A two pixel middle line wouldn't look that bad

Very nice! The number of colors do seem a bit too much thoughYou could still retain the same amount of detail with less colors with the use of dithering. It looks very similar, if not exactly the same regular size. Also all the front facing sprites could be 1 pixel wider, but that's just me. Of course these are just suggestions, do whatever you please These are great

Try to make the matoran poses more fluid. The legs and arms seem very stiff. Give them bendable knees and elbows!