I don't think it would hurt if you'd cool his colors a wee bit...

<<Original

Shading is a nightmare. Seriously look at the eyes- they are flat! Look at a ball and imitate the shading.
The eyebrows are levitating above the face?

Also I have to agree - this is more zombie than hobo- go watch "Life Stinks" by Mel Brooks

Aaand if you're too lazy and just doesn't care about your piece, here's a still from the movie
http://www.imdb.com/media/rm90552832...ef_=tt_pv_md_1

Took the liberty to also show you how beards are grown - downwards. Not in doughnut shapes. Also fixed eyes



Please note that this is a very quick edit. Like 10-15 min. These are only pointers.