For some perspective, note that this tidal wave comes on top of the 2010 wave. One would have thought that the Republicans had already reached as high as they could after all the offices that they took in 2010. But they actually have one more governorship than after 2010 and more state legislatures.
Republicans have picked up
Colorado state Senate (possibly the state House), Maine state Senate, Minnesota state House, New Hampshire state House, New Mexico state House, New York state Senate, West Virginia state House and a tie in the Senate, Obviously not all the results are in yet, but Republicans now control both houses of 28 state legislatures as well as the single house in Nebraska.
Even in Pennsylvania where Republicans lost the governorship (the only one that they lost), Republicans added 8 state house seats(119-84) and 3 senate seats (30-20).
UPDATE: Add in both houses in Nevada and the Washington state Senate. The NCSL has this summary:
It appears that Republicans will have a net gain of between 350 and 375 seats and control over 4,100 of the nation’s 7,383 legislative seats. Republicans gained seats in every region of the country and in all but about a dozen legislative chambers that were up this year. . . .
(Click on figures to enlarge.)