The exploding reflector model has been the basis for wave equation post stack migration. It enables imaging of zero offset data with one downward continuation step, as opposed to the multiple downward continuation steps required in pre-stack migration. However, the exploding reflector model does not account for reflections for which the corresponding down-going ray path differs from the up-going ray path. By means of a synthetic example which includes a high velocity inclusion, different alternatives for imaging of zero offset data are tested. The results show that the restriction to identical down-going and up-going ray paths causes discontinuities in the image of reflectors in regions beneath the high velocity inclusion. The limitations of the exploding reflector can be overcome by using multi arrival Kirchhoff migration, or for wave equation imaging, using pre-stack migration algorithms for the imaging of post-stack data. Both alternatives require an economic price.