i'd suggest something more like this sort of size/pose:

Reasons -
I didn't measure that, but i imagine something like it would work well with most of the standard tile sizes.
Smaller is better when it comes to animations because it MUCH MUCH FASTER to pixel a small character
Round "beanbag" body type makes for cute, bouncy animation as befits a penguin, with plenty of opportunity to show weight OR weightlessness when needed
Two-handed sword makes the character balanced and also forces him to present his front to the viewer. this can be done if he fights closed with the single-handed sword, but in your sketch there you've got him fighting open which makes him face in profile at best, away from the viewer completely at worst.
Huge weapon size compared to character adds to cuteness factor
Another last thing i'll suggest before i go - you really should pixel the sword fresh at each angle if you want it to look good. Autorotate functions just suck for pixelart i'm afraid
