GRIMLOCK

the rear, right behind the legs has...structual issues, as do the legs & the arms, the head is...odd take another look at some reference, the spine is wrong.
on the bright side you have plenty of detail (although it almost detracts from the peice rather than adding to it) & the beck is almost right, almost.
also the poor scan takes a lot out of this piece. try to keep it flat as it scans. also it would greatly benifit from some touch up & a repost