It looks like you resized this image horizontally or something (or possibly moved it) and I'm guessing you're using photoshop or something similar, so it' made the piece blurry-looking.  There are a lot of 2D animation resources out there, a lot of it just happens to be made for traditional 2D animators rather than pixel art / sprite animation.

http://www.wayofthepixel.net/pixelation/index.php?topic=3467.0

There are a few animation tuts in that thread, as well as several other tutorials and articles you'll probably find useful.  I don't know what app you're using for this, but I'd suggest starting out with something that specializes in pixel pushing.  Photoshop will work in a pinch, but it's not the easiert pixelling tool to set up.  Graphics Gale and Pro Motion are probably the most popular apps for pixel work, but I've found Allegro Sprite Editor and Grafx 2 to be pretty solid as well.

You should probably re-pixel this to fix the blurring issue.  It's hard to give anything but basic crits when it's hard to tell if something is AA'd or if it's just a blurring glitch.  I will tell you that in the front-facing walk animation you've got the arms and legs moving together when they should be opposing one another.  Left foot forward + Right arm forward.  You've got it right in the side-view animation, but in the front view the left arm and leg move together, as do the right arm and leg.  There are shading issues as well.  The light on the leg is coming from above in one frame and below in another frame.  It'll be easier to animate if you ignore much of the shading and just focus on the movement first.  Then after the movement is good you can go in and add some shadows or highlights.

So this guy's a cave explorer?  Have you done any character stuff on paper for him?  If you can get him to look about right on paper, you'll probably find it a lot easier to pixel him.

You might want to look into some more reference that has some of the topographical information you might be able to show on such an image, but then it all depends on what your goal is for this.  Are you going for a realistic sort of image, or are you going for a stylized / exaggerated feel?  You might not be able to see mountain ranges in that reference, for instance, but it might make the image more interesting to look at if there were some more speciic details on the globe.  Right now what you've got in Spain is just noise, really.  Are there mountains there?  Forest?  There's a dark spot in Africa with some more pixels dotted around it...  what is that spot?  It might be more appealing to visitors to see something that would represent what those areas actually are.  The piece is also really large, which is great if you think you can pull it off.  I don't think I'd be able to.  You might want to think about cutting the resolution in half, but then if this is a website image and you want it large then more power to you.

For the record, the bit you call Alaska is actually Greenland + some of Canada.  The little white dot below Greenland on the ref is Iceland, which you should add.  Madagascar and Japan should probably get on there as well, tho I'm probably just getting ahead of myself.

Bottom line:  If you're gonna try to make this look reasonably 'real' or detailed or accurate, I'd suggest getting some more ref so you'll know when to break from this particular reference and add maybe the odd detail that might not be all that evident on that image (like the Nile, which is a pretty huge landmark, but isn't very easy to discern on that ref.)  And I'd suggest blocking out the land masses - especially the shorelines - with a lot more accuracy before you start jumping into detailing much of anything.  Getting the outline and proportions of a landmass right is key to making it recognizeable.  India / China / Russia shoreline is pretty far off, The mediterainean area could use a lot of work (Italy is there, but doesn't look like Italy, Greece is missing entirely).

Simple world map: http://info.comegoogle.com/phone/world-map.html

I'm not really the best Pixel artist from a technique point of view since I just recently started pixeling, but like a lot of other people I started out with traditional drawing experience.  I was interested in it as a kid, but like a lot of kids I got frustrated by my lack of "talent" in my teens and stopped for a long time.  I doodled off and on, but it wasn't good and because I wasn't really studying anything - just doodling crap - I didn't progress very far.  I got back into drawing in my mid 20's and have been starting to get into digital painting and pixel art recently.  I'm 30 right now, and while that's probably older than a lot of people on these boards, that in no way makes me better at art - I'm sure most of these guys could draw and pixel circles around me - so I don't think age has much to do with it at all, aside from maybe having more life experiences to draw from for inspiration.

The great thing about art in general is that everything you learn in one medium will inform every other medium you work with.  If you paint a lot of drapery studies then go to sculpt that sort of thing, your sculpt will look better for it, and vice versa.  Don't just pixel.  Draw, paint, do whatever you find interesting.

Another thing I learned is that you'll learn more by studying things rather than just drawing them.  I mean, sure, you can take a pine cone and draw it a few times, trying to be accurate and trying to make it look just like that pine cone, but you'll learn a lot more about pinecones and how they work if you take a pinecone and rip it apart, really study it, draw the pieces, make notes about the texture, the colors, the sound it makes when you snap it, the smell of it...  hell, the way it tastes.  Take notes and use a sketchbook to really look at things beyond just the surface - beyond just looking at something and drawing it.  The next time you draw a pinecone you'll take all that stuff and try to communicate it, and you'll have a better idea of how to communicate it.

But it's easier to learn what's right if you know what's wrong.  Screwing up and realizing it is pretty much the best way to learn everything.  Hell, it's the only way to learn anything.  You don't just pop out of the womb with a perfect grasp of your naitive language.  You have to say one word incorrectly a million times and be corrected a million times by your parents before you've learned that first word.  Everyone can learn how to draw and be a great artist in the same way that everyone can learn the language their parents speak.  But, you'll notice that a lot of people don't actually get that great a grasp of their naitive language.  They can speak it and communicate basic ideas, but not many people learn the more complex words and propper grammar.  Art is the same way.  Anyone can just pick up a pencil and make a picture.  The quality of the results relies entirely on how much time they've spent really studying it.

So keep working at it, cause the more time you put into it now, the better you'll be down the road.  Take it from someone that waited till they were in their 20's to start really learning.

Welcome to the boards

I'm gonna start from the bottom and work my way up from there:

The feet feel off to me for a couple of reasons.  First, they're both flat on the ground plane, which doesn't really look natural, but also because of the way they're pointed.  She's more or less facing towards us, yet the foot directly under her is a side view, which is hard to do if you try doing it yourself.  Here's an edit to show what I mean:

Personally, I think that feels a bit better.  Not the best edit in the world, but you get the idea.

From the waist up she looks pretty good.  The hands could use some work.  It looks like she's wearing mittens and her hands are kinda small.  I like her face and the head, but you can see the scyth behind her head, and that should be covered by hair.  The blade on the scyth is also a side-view sort of thing, and if she were holding it to the side like that it would be going THROUGH her head, not behind it. The coat looks good until it gets down to the waist and the legs and then it keeps spreading out.  It'd look more natural if it fell more vertically down, and maybe if it draped around her instead of flattening into a triangular shape.  There's a hint of a curve on the left side (our left), but it still feels very flat.

The pole on the scyth doesn't look like it would support that much weight, but I figure that's just a stand-in or something.  If it's not, then you'll probably want to give that some more weight, and maybe make it more than just a straight line.

I won't really comment on the pixeling work, since I'm also pretty new at it and I've not got a great handle on that aspect yet, but there are some red pixels at the top of both legs that don't seem to add much.

Anyway, you mentioned that you didn't use any reference, and i'd say that you probably should.  Not pixel art reference, but photographic.  Look at photos of people in a similar pose, or grab a mirror and be your own model.  Best way to learn how to draw, paint or pixel something is to look at what it is you're trying to replicate.

Are you going to color them or leave them black and white?

I'd say, if you do decide to color them, go with something a lot more subtle than your previous color versions.  Mostly black and white, but with some color trim here and there to pop them out a bit or something.

Love the idea.