It looks alright so far, but I think you should make things... bigger and more messed up because right now it looks like a trapezium with random stuff inside it. It's also kinda hard to see at first sight what is in that trapezium, maybe you should make the teeth whiter or something. Also, why is there a giant red penis on the back of it?
I like were its going, based on the real deal, i'd say brighten the mouth a bit, its very dull right now, nothing really pops out.
Keep working on it, its looking good.
And as stated before make the back a little more detailed.