The low color one is fine, it looks very much like the 'inked' art style of the comic. The other one doesn't benefit much from more colors, the one-pixel dark blue buffer only muddies the edges between blue and black.
Note that you shouldn't use rendered fonts (text) and vectors (the logo) in the gallery
Yes!! I love the Phantom! This era of superheroes needs more representation, like the Shadow, Dick Tracey, asks the Rocketeer. I've been wanting to do a Rocketeer pixel for awhile and I think you've inspired me. Great work! I like your antialiasing. The only spot I noticed it could use a little bit more antialiasing is the vertical line defining the ab muscles. I don't see anything else that needs attention. Great Job! I hope you make more of these. 
Oh! Sorry about the logo, I didn't know. And thank you for your educational comments.