Open source game engine version developed by Croteam for
Serious Sam Classic included First and Second Encounter with vulkan support.

Serious Sam: is a high-adrenaline action-arcade shooter heavily
focused on frantic arcade-style single player action. In a world where cyberpunk
meets fantasy-fiction and advanced technology is mixed with black magic
and psycho-powers, Sam travels through the beautiful world of ancient Egypt
and several diverse planets, confronting countless Mental's minions on his way
to the Mental's base.
