The Bund Tourist Tunnel is a strange and rather garish way of making the journey under the Huangpu River to Pudong. You might get a few laughs from the light displays. Otherwise, you can take the metro on Line 2 to Lujiazui, or catch the ferry from the Bund.
Outside of the Lujiazui metro stop and Century Park, Pudong is not a pedestrian-friendly area, as there are large, rather featureless distances between the sights. You can either take the metro to get around or jump in a cab. If you visit all the sights, you could easily spend a day out here.