On the average human, arms extend approx halfway between the knee and hips. Your arms are stopping at your hip cutting off about 10 inches in length. Also, you take the shirt in a little at your waist, but then you cock your arms outward like your hands are in your pockets... this just looks weird, although I do agree that keeping your chest in one straight shape looks weird too. Last thing, your trapezius is too long, unless you're extremely muscled it's going to be a relatively steep slope between the neck and shoulders. That's what I decided I was going to try and change on a redraw; while drawing I discovered what may be the cause of a lot of frustration, your charater is one pixel wider on his right side (the left side of the drawing.) So I fixed that. Then I discovered the reason that you probably did it. You cannot draw a two tone arrow with a shaft of two pixels, nor can you draw a "pointy" arrow with a shaft of two pixels, so you threw the extra pixels in there, which made his body wider, which made it didfficult to make him look symmetrical, which made his head look crooked, etc, etc.
So I took out the extra row of pixels. I know you would like to have an arrow on his shirt, but it just causes more problems. Animating, Side view, size of character... at some point you have to weigh your options. I say lose it. After that, I played with the colors to get something that felt right. Your yellow was a little TOO yellow for my tastes, so I lightened it up a bit, then I selected a second yellow to give his chest some depth and to do one of the things the arrow used to do, whoch is break up that solid yelloe space.
there are some other changes, minor but see if you can figure them out.
The sprite is 19 x 50 pixels, that's including the 1 pixel padding. The sprite is therefore 48 px tall and 17 px wide.
Something I ant you to do is the 5 shades test. Black & White, then all the secondary colors: Green, Orange and Purple. I like to use a more purply purple usually, but you already had a color you were using so I stole it. =P
This is going to let you see how he looks on a variety of colored in backgrounds, it gives you a better impression of how your colors harmonize.
Using this, your pants blended in too well on the green and black screens, so I lightened them up a little and skewed them towards purple over green. The neck looked long on purple, orange and white, so I took it down one.