  The invariant cross sections for direct photon production in hadron-hadron
collisions are calculated for several initial energies (SPS, ISR, S$p \bar p$S,
RHIC, Tevatron, LHC) including initial parton transverse momenta within the
formalism of unintegrated parton distributions (UPDF). Kwieci\'nski UPDFs
provide very good description of all world data, especially at SPS and ISR
energies. Inclusion of the QCD evolution effects and especially their effect on
initial parton transverse momenta allowed to solve the long-standing problem of
understanding the low energy and low transverse momentum data.
