The electronic structure of ZnSe-ZnS strained superlattices is studied within the framework of an ${\mathit{sp}}^{3}$${\mathit{s}}^{\mathrm{*}}$ empirical tight-binding approach. This system has been shown to have a vanishing conduction-band offset. Based upon this result, unusual confinement properties of the lowest conduction states at the Brillouin-zone center are found. This is in marked contrast to barrier-well superlattices. Oscillator strengths are also estimated. It is found that the usual \ensuremath{\Delta}n=0 selection rule breaks down.