if are walking around Namba and Dotombori, u may try something special here...curry rice at dotombori and Golden Dragon ramen.

you can go to Shinsaibashi shopping street. There is a crab specialty restaurant you can have all kind of crab dishes or sushi restaurant with live fish tank for the freshest sushi and near the end of it there is a fugu (blow fish) specialty restaurant I believe serves farm raised fugu (not poisonous)

In Osaka you have to try food call - Okonomiyaki, its so yummy yummy =)) definitelly