Was the unpopularity of the demoocratic government in Japan in the 1930s mainly brought about by economic conditions?
Yes and no. Japan, like much of the rest of the world, was in the economic desert of the Depression, although it was not quite as bad as in other countries at that time. Japan had come out of the war with Russia near the turn of the century and World War I as a power on the rise.
But economic conditions were only part of what was challenging Japan's democratic government at that time. Japanese nationalism - the belief that The Empire of the Rising Sun was superior to other races and nations in the world, and should take its rightful place as the rulers of the region - was quickly gaining popularity. Fascism was a popular government form of this nationalist fervor, and like in Italy and Germany, such militarist sentiments gained ground and put a stranglehold on more democratic elements in Japan in the 1930s, giving rise to the military dictator Hideki Tojo.
Adding to the nationalism at the time was Japan's military successes in its war against China in the 1930s.