We review the characteristics of nucleosynthesis and radioactivities in 'Hypernovae', i.e., supernovae with very large explosion energies ( 10^52 ergs) and their γ-ray line signatures. We also discuss the ^44Ti line γ-rays from SN1987A and the detectability with INTEGRAL. Signatures of hypernova nucleosynthesis are seen in the large [(Ti, Zn)/Fe] ratios in very metal poor stars. Radioactivities in hypernovae compared to those of ordinary core-collapse supernovae show the following

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... s: 1) The complete Si burning region is more extended, so that the ejected mass of ^56Ni can be much larger. 2) Si-burning takes place in higher entropy and more α-rich environment. Thus the ^44Ti abundance relative to ^56Ni is much larger. In aspherical explosions, ^44Ti is even more abundant and ejected with velocities as high as ∼ 15,000 km s^-1, which could be observed in γ-ray line profiles. 3) The abundance of ^26Al is not so sensitive to the explosion energy, while the ^60Fe abundance is enhanced by a factor of ∼ 3.