Looks good, although there are some issues with proportions. The only way to get better than you are now is to practice and be super-critical with proportions and texture quality. I think it's a bit like the transition from novice to skilled. If you keep improving, then you can go onto professional quality modelling, if you accept that as the best work you can do, then it's the best work you'll ever do. I think you could make the push, and tighten up those skills to the point where you can make well proportioned human characters at a high quality level.
I hope you understand what I'm trying to say...
For example, the eyebrows. It's an alien character so nobody can say that those eyebrows are too basic, because they might well be spot on. But we all know that aliens are often a proportion cock-up cop-out, just like making somethings head big and calling it cartoon. The hands are another weak point IMO too. But say you were hyper-critical about them, like you decide that the character has to look human, the eyebrows have to look right, the hands have to have the right proportions. You would study some anatomy, take the time to get the proportions and sizes as exact as you can - but then the model would look about 5 times more professional. Eyes and eyebrows, hands, noses, mouths.... it's where amateur modellers become pro.
Now I'm not a great modeller, I can do mechanical things like guns but organic modelling tends to have to be created mechanically for me to do anything like a decent job. But one program that I really like is Makehuman - it creates high polygon human manequins. Too high polygon counts to use in a game, but you get a really well proportioned model nontheless. What I would do is use Makehuman (it's free and easy to use) to make a manequin in the proportions I need, then use it as a guide, or even use it to render the normal map. But anyway, it's really useful to have a manequin to base a model on, less guesswork and less need for concept art. The Makehuman polygon structure and complexity makes it less than useful for direct media creation (much like poser), but for making guideline models it's damn useful, I wouldn't try modelling a humanoid character without it.
Health, Ammo, and bacon and eggs!
