  The recent results on the main soft observables, including hadron and photon
yields and particle number ratios, $p_T$ spectra, flow harmonics, as well as
the femtoscopy radii, obtained within the integrated hydrokinetic model (iHKM)
for high-energy heavy-ion collisions are reviewed and re-examined. The cases of
different nuclei colliding at different energies are considered: Au+Au
collisions at the top RHIC energy $\sqrt{s_{NN}}=200$ GeV, Pb+Pb collisions at
the LHC energies $\sqrt{s_{NN}}=2.76$ TeV and $\sqrt{s_{NN}}=5.02$ TeV, and the
LHC Xe+Xe collisions at $\sqrt{s_{NN}}=5.44$ TeV. The effect of the initial
conditions and the model parameters, including the utilized equation of state
(EoS) for quark-gluon phase, on the simulation results, as well as the role of
the final afterburner stage of the matter evolution are discussed. The possible
solution of the so-called ``photon puzzle'' is considered. The attention is
also paid to the dependency of the interferometry volume and individual
interferometry radii on the initial transverse geometrical size of the system
formed in the collision.
