Hi anguyen, Thanks for sharing your work with us! This is another oustanding piece from you, and I must say, it gives me great pleasure, as it does with the work of Zack Patroc, when I see such precisely formed, carefully crafted models - have I already thanked you for posting? 
Naturally I have nothing to critique but I wonder if you could share with me what is your method of working in achieving models to this effect?
I’m referring not so much to the usage of particular tools but rather to principle methodologies/workflows.
For instance, that in generating both large volume and fine detail you take recourse purely to focusing, sequentially, on specific muscle goups - something akin to covering a skeleton with muscles ? ( As in Zack Patroc’s DVD)
Thanks,
Kircho