They are horrible. Really horrible. Perhaps I can give you the medallion of the most horrible death sound ever. Shoot someone in the face and they'll scream for 3-4 seconds and that death sound sounds like that one horrible squicky duck everyone's seen in the internet. Oh, also, why in the heck do they scream "SNIPER" after the sniper has shot them in the face? This has happened many, MANY times.
This game has gore, please redo the sounds what a human propably sounds like when someone shots him/her in the face. it's not IIOOOOIIIIIUUUUOOOUUUOOOUUIIIUUUUOOOO, it's something much, much more horrible. See some movies.