It's probably not an unreasonable assumption that the rodent seen in the foreground is a pre-mutation Splinter, but who knows?
The image does seems very similar to how it was described months ago, when a toy blogger described it as having "pointy edges coming off of absolutely anything." That same blogger speculated that this latest incarnation of the character wouldn't endear himself to fans and would become the stuff of ridicule for some time -- and while time will tell whether that's true, certainly early reactions from fans and the press online haven't been charitable, with many comparing him to one of the Michael Bay Transformers (Bay produced TMNT).
This version of Shredder has been one of the more talked-about and sometimes controversial elements of a very talked-about and controversial film, since he was transformed from a mysterious Japanese character to a white man whose backstory is apparently tied in with Megan Fox's April O'Neil. Inherently, that meant changing the character's real name to something less obviously Japanese.
Comic artist Rob Liefeld joked that the design was reminiscent of his X-Men villain Stryfe.