The Thumb idea isn't such a winner the second time round. ThumbTanic wasn't as good as Thumb Wars for a number of reasons. Primarily, I think, Mr Oedekerk had far less to work with in the Titanic send-up. Unlike Star Wars, the movie Titanic hasn't (yet?) become a cultural myth and there are far fewer references to be made which will resonate with the audience.
In ThumbTanic, the holes are filled by one-off jokes which don't really seem related to anything. For example, the hero's insinuation that the heroine isn't clean during the "jump off end of ship" scene - it's not funny. Rather, you just think to yourself, "Did I miss something in the original movie?". There were too many of these type of baseless jokes (cf. arachnid).
By contrast, the send-up of the smarmy ship's designer had meaning and was funny. Also very funny was the send up of the bloke in the movie who wanted to go "faster" as a maniac running around demanding *everything* be "faster" including the sinking of the ship and himself being the first to die. These sort of jokes meant something in the Titanic context and lent meaningful humour to Thumbtanic.
The thumb "media", the faces and the voices, are still amusing. The props and sets and the CG animation are worthy of appreciation. Overall, although ThumbTanic proves that quirkiness alone won't work, this filmette still keeps you amused and chuckling to the end.
