  Dynamics of relativistic heavy-ion collisions is investigated on the basis of
a simple (1+1)-dimensional hydrodynamical model in light-cone coordinates. The
main emphasis is put on studying sensitivity of the dynamics and observables to
the equation of state and initial conditions. Low sensitivity of pion rapidity
spectra to the presence of the phase transition is demonstrated, and some
inconsistencies of the equilibrium scenario are pointed out. Possible
non-equilibrium effects are discussed, in particular, a possibility of an
explosive disintegration of the deconfined phase into quark-gluon droplets.
Simple estimates show that the characteristic droplet size should decrease with
increasing the collective expansion rate. These droplets will hadronize
individually by emitting hadrons from the surface. This scenario should reveal
itself by strong non-statistical fluctuations of observables.
