I don't consider myself an expert on this particular thing, and I am unfamiliar with your source material, but I might as well attempt feedback if no one else is.

First off, excellent work. You are dedicated to the craft and it shows. From here on out, I'm nitpicking.

You seem worried that he may appear too feminine. Conventionally, rounder head shapes and softer features are used to depict cuteness, femininity, and/or youth... whereas slimmer and sharper angles in the face help denote masculinity, maturity and feels more imposing. Similar rules apply to eyes where big and round a glistening is hard to reconcile as masculine.

Designing a young male character yields additional challenges in the various anime styles. Countless other features that signal male gender like strong jaw lines, muscles, Adam's apples, thicker eyebrows, facial hair, etc. don't make as much sense for young adults, and many of the remaining features of young guys similar are often handled similarly to girls.

In fact, I'd consider Sora from Kingdom Hearts to actually have a very feminine face. If his hair was different, he could cosplay as Princess Zelda. He may come off as a young male because there is a good deal of external context. The game designers do have a few tools you don't which help them override that perception. For example, working with still frames precludes clues coming from things like voice acting or animation.

There are a lots of other little clues that you can adjust, but the general impression of femininity can come from a sum of the parts, and no lone piece of advice I can give would necessarily make or break the difference.

I hesitate to give any absolute advice not only because anime is not my field of expertise and because all the touches I would make are revising subtle gender clues, where keeping any individual change could be a valid stylistic choice making the character unique from common tropes.

Perhaps I can list the collection of subtle clues I'm noticing that may contribute to the feminine impressions, and you can consider experimenting with ones you choose at your leisure:

1. The bulge of more distant left cheek could be less rounded and slightly narrower below the cheekbone.
2. The body language. He looks like he is posing for a fashion shoot. If he was scratching his head or put his hand up there while contemplating something, instead of taking a modeling gig, he might have a more serious expression. (Changing the pose this late may be painful, since the existing work shows a diligent investment.)
3. The soft features / soft facial lighting. Calling attention to cheek bones is contrary to some anime and not others, but generally helps masculinity.
4. The hair style seems more gender-ambiguous than Sora. It may be more prevalent on guys in anime then I realize, but also I know women with this haircut in real life. However the darker color choice works well for the hair (as opposed to some feminine pastel color.)
5. The thickness of the eyelashes, especially on the outer edges could be reminiscent of mascara.
6. The tilt of the eyes. I see males more often to depicted with eyes rotated in and down along the nose, and women with eyes tilted up along the nose and down on the outside edges.

I scribbled shadows over your picture with a quick mock-up of some of the changes similar to how I imagined them just for a quick visual reference. Feature defining shadow, serious expression, etc. I didn't do much cleanup or preserve transparency. Again, all the changes are stylistic (but conventionally masculine) and not necessarily an improvement. Depends what you are striving for.



PS: If you want to reduce the size of source images to declutter your post, modify the first tag before the image the URL to be of the format "img width=200". People will still be able to click to expand them.

I'm trying to give my little game a more appealing and readable HUD than the current one. It's a DS homebrew game, and I gave myself the whole "bottom screen" for stats & score. The text in white will be code-generated and offers little artistic liberty, but I thought the "health bar" and the "punch bar" could be worth a more visual interpretation : the blue curves.

The intent is to lit on/off part of these curves (palette-wise) to reflect the current status of the hero.

I'm not yet satisfied with the double-size Bilou (blue hero) and Applemen on the lower half, though.
Any hint ?

This looks very refined already. And it's definitely appealing to the eye.  

As for possible improvements on the lower screen:
The background looks like it has some copy paste errors. (I see six or so straight line cut offs for the leaf clusters.)
...On that note, there seems to be a black square corner behind the apple. It kind of overpowers and detracts from the apple's subtle mouth.

Also, The leaf/stem of the apple seems to be lost in the background atm. It helps that it already has a different hue than the blue forest tint behind them but maybe you could create in inner semitransparent box that overlays the background enough to push them forward.  
Here's a quick photoshop example.



It might add linearity and structure to what looks very organic and irregularity already while cuing to the player that the screen is of lesser importance. Not that the text was hard to read before, but this doesn't hurt.

The health bar seems very reminiscent of a jump bar right now. I'm not sure if I'm the only one reading it this way though.
...The classic direction for the health bar to drain is right to left, but in this case, that would disconnect you character for your remaining health.
Perhaps you could try pushing the blue guy to the left of the bar and maybe altering the bar's shape a little.
Of course, this wouldn't be a problem for people who who have played the game before, but it might be counter intuitive for people just picking it up.  

Just my two cents... Hope this helps!

Hmm, is this going to be over a background?

Few things I'm seeing:
First off I'm always hesitant to use a completely solid black, but if that your intentional style, all the power to you.
...The dimensions seem a bit off, but again the context is important. If this is going to be in game and the range of this weapon needs to be reduced, you can always fudge it a little. Lastly, I'm concerned about the chain-- not only does it feel more like a zipper instead of a chain, but it looks like they lose shape around the curve, making a square-like notch cut out of it.

Reference pics are underrated. I've found them to be invaluable at times, even though it might seem like more work.

Excellent stuff man. Thanks a ton.
Sorry I've not been around as much...
I've been backed up a little lately now that schools starting for me, but I definitely plan to keep going with this. 

@ Singularity = Appreciated the edit. I will download the edit. Also, it's supposed to be a male teenager haha, it's what happens when it's a 20+ minutes quick work...

oh, haha. My bad...

If you don't mind, I feel incline to try doing a second conceptual edit.

What may be working against you here are the hair, eyes/eyebrows, and neck. The hair seems a tad long in the back for a dude. Most guys with hair that long in the back end up with the mullet shape. The eyes might play an even stronger role. The outlining of the male eyes works in amine sketches because the lines are so thin. When reduced to pixels, they are thick and dark enough that they begin to look like eye liner. This 'mascara illusion' is working against you. As for the eyebrows and neck, I think you might want to aim for making them bushier and broader.



Hope this helps.