1; in places outside of Australia it is loosely used as synonym for sorted.
2; however for all those in the know in Australia it is used as a synonym for dodgey or poorly put together.
1; person "hey james how much of the homework have you done?"
me "most of it but i have the rest "sussed"
2; me "crap mate that burger you brought is "sussed" ass"
person "whatcha expect, its from maccas"