I'm surprised that this movie has been so universally panned ... it was really quite entertaining. I guess there are a lot of rabid Jim Carrey fans who feel that you can't have a Mask movie without him and are viewing this movie through those filters. Frankly, I thought that "Son of" was more coherent than the original, with a very compact plot that made sense within its parameters. If you take away the fawning over Carrey (whose shtick gets old for me fast), the first movie was about CGI, and it's only moreso in the sequel, plus this has more emotional hooks.
Actually, the trailers for "Son of" make it look like there's more "whacky stuff" going on than is the case, as large portions of this film deal with developing the skewed dynamics of the two families involved. The movie is almost more about Alan Cumming's Loki (who has been ordered by Odin to get the Mask back) than it is about Jamie Kennedy's sad-sack cartoonist ... certainly Cumming gets most of the cool bits (plus, in a possible dig at / homage to Carrey, all these goofy characters to do). I though that the casting was dead on, including "gratuitous star turns" by Ben Stein and Steven Wright which were amusing rather than irritating (the only "wasted" role was Bob Hoskins as Odin ... why bother casting a well-known character actor if the portrayal is so generic that it could be anyone under the makeup?). I hate to say it, but this movie reminded me a lot of the Garfield movie (but in a good way) as it was a sweet little movie that told two or three story arcs competently, and served to frame the CGI treats (which, as I noted, came and went through the movie) nicely.