Because the theatrical release of Piranha 3DD was limited (it went to VOD quickly), fans of the original Piranha 3D had no legal way to watch the sequel in many regions. iSaIDub filled the void.
The special effects are, of course, the main attraction here, and the piranhas are impressively rendered. The gore and violence are plentiful, but it's all presented in a way that's more cartoonish than realistic. piranha 3dd isaidub